Medicine and human nature

Medicine likes to imagine itself as a profession governed by evidence, restraint and humility. We ask patients to trust us because our decisions are supposed to rest on facts rather than vanity, and we teach younger doctors to question themselves, revise a diagnosis when the evidence changes and accept that another colleague may have seen something they have missed. We speak solemnly about service, duty and the privilege of healing, and much of that language is sincere. Yet doctors remain human, and the white coat does not abolish pride, rivalry, insecurity or the hunger for recognition. In some circumstances, the culture of medicine may even magnify these tendencies, because the same qualities that allow someone to achieve something exceptional can later make it difficult to tolerate contradiction, share credit or accept a more complicated version of history.

This becomes particularly apparent when questions of scientific priority arise. Who was first, who had the original idea, who performed the first operation, who designed the instrument, who published the first series and who gave the procedure the name by which it became known? These sound like factual questions, but they are often also questions of identity, because the issue is not merely what happened and when, but who deserves to be remembered and whether recognising one person’s contribution necessarily diminishes another’s. Scientific and medical advances rarely arrive fully formed from one mind. One person establishes the principle, another develops the enabling technology, someone else recognises the clinical possibility, a surgeon makes it workable, a research group demonstrates safety and others refine, teach and disseminate it. The final procedure may eventually appear obvious, but it was not obvious at the time; it was built gradually, often by people working in different countries, sometimes without knowing what others were doing and sometimes approaching the same problem from entirely different directions.

Why history wants a hero

History prefers a hero. Institutions want founders, prize committees need recipients, journalists need a central character, companies want an origin story and conference introductions reward simplicity. “He made a decisive contribution to the development of the procedure” gradually becomes “He invented the procedure”, because the second version is shorter, more memorable and more useful for institutional mythology. Over time, the story may become inseparable from the person. The discovery is no longer simply something he helped create; it becomes the organising narrative of his professional life, reinforced by awards, repeated by colleagues and accepted by younger doctors who were not present at the time. Eventually, the person himself may come to depend upon that account, and historical nuance can then feel less like accuracy than dispossession.

The distinction between being a major originator and being the sole inventor may seem small to an outside observer, yet to someone whose reputation has been built around the latter description it can feel existential. Recognition of a predecessor may be experienced as an accusation, while evidence of simultaneous development elsewhere may feel like an attempt to diminish a lifetime’s work. This is where confidence and insecurity begin to resemble one another. A secure pioneer can acknowledge that others created essential parts of an advance while remaining certain that his own contribution was decisive. A more fragile response requires the significance of every other contributor to be reduced, so that earlier work is reclassified as irrelevant, parallel development is dismissed as fundamentally different and historians become adversaries. At that point, the argument is no longer really about evidence; it has become a defence of identity.

That does not necessarily imply dishonesty. Human memory is not a recording device, and we reconstruct the past through the meaning it later acquired. An early experiment that was tentative and uncertain at the time may, decades later, be remembered as the fully formed beginning of everything that followed. Conversations become clearer, chronologies become neater, doubt disappears and the final success casts its light backwards over events that were far less certain when they actually occurred. A coherent narrative is gradually created out of what was originally a messy sequence of partial insights, technical failures, parallel experiments and uncertain beginnings, and the person telling the story may sincerely believe it because memory has fused the final outcome with the earliest stages of the journey.

There is also a tendency to confuse different forms of priority. Conceiving an idea is not the same as performing an experiment, performing an experiment is not the same as treating the first patient, and treating the first patient is not the same as publishing a clinical series or making a procedure safe and reproducible. Naming a procedure is another achievement, as is teaching it, standardising it and bringing it into widespread clinical practice. These accomplishments may belong to different people, and their historical significance cannot always be ranked by a single date. A patent may establish legal priority without establishing clinical achievement, a conference presentation may precede a paper but leave only a fragmentary record, and an operation may have been performed before it was adequately documented. Two groups may also reach similar conclusions independently, with neither knowing of the other. There may therefore be no single throne upon which to place an inventor, however strongly later generations may wish to create one.

Ambition, prestige and the culture of deference

Medicine remains attracted to that throne because it is not only a scientific enterprise. It is also a hierarchy of status in which reputation determines appointments, invitations, honours, research funding, commercial opportunity and the degree to which future claims are believed. Being first matters, and ambition is not in itself a defect. Many important advances have been driven by individuals with unusual determination, self-belief and resistance to criticism, who persisted when others thought their ideas impossible and continued despite ridicule or professional opposition. The temperament capable of genuine innovation is not always naturally modest, and nor should humility be romanticised to the point of denying legitimate accomplishment. Scientific history can be unjust, and important work may be overlooked because it occurred outside the dominant institutions, appeared in an unfamiliar language or lacked access to influential journals and meetings. Defending one’s contribution may therefore be entirely justified, and at times necessary; the problem begins when preserving rightful credit requires erasing everybody else’s.

There is a particular irony when this happens among doctors. Our moral authority rests partly upon the belief that we can place another person’s welfare above our own needs, and we expect clinical humility in the form of recognising complications, reconsidering diagnoses and seeking help when necessary. We teach trainees that certainty can be dangerous and that the body does not obey reputation, yet professional legacy activates a different part of human nature. The healer becomes the claimant, the colleague becomes the rival and evidence may be welcomed when it supports the preferred account but subjected to increasingly severe standards when it threatens it. Scientific scepticism is applied asymmetrically, although those applying it may remain entirely convinced that they are defending truth rather than defending themselves.

Prestige does not protect against this and may make it worse. Highly accomplished people are often surrounded by deference, their confidence has repeatedly been rewarded and their ideas have proved correct when others doubted them. Their names become attached to techniques, devices, lectures and institutions, while fewer people challenge them directly. After enough years, contradiction can begin to feel unfamiliar and even disrespectful. There is also a collective reluctance to correct the record, because there is little reward in confronting an older or revered figure and considerable professional risk. Institutions may prefer a convenient mythology to an awkward reassessment, while younger doctors may depend upon the person concerned. The simplified story therefore survives, not always because everyone believes it, but because nobody wishes to disturb it.

When the challenge eventually comes, it can feel more hostile than it was intended to be. Someone who has heard one version repeated for decades may reasonably wonder why the objections have appeared only now, and the correction may be experienced not as scholarship but as betrayal. This is one reason scientific history should not be written as a prosecution. Its purpose should not be to dethrone one hero and install another, but to distinguish carefully between conception, experimentation, publication, clinical development and dissemination. It should acknowledge uncertainty where the documentary record is incomplete, accept that independent discovery is possible and resist the temptation to assume influence merely from chronology. Most importantly, it should not turn shared achievement into personal defeat, because a mature account of innovation does not make great contributors smaller; it often makes their true achievement clearer.

The sacrifices that greatness demands

Medical greatness rarely arises without sacrifice. The people who change a field are often those who work longer, tolerate more failure, absorb more criticism and remain committed to an idea after more cautious colleagues have abandoned it. They may spend years resisting accepted wisdom, accepting financial or professional risk and devoting an intensity of attention to their work that most people would neither choose nor sustain. These qualities deserve admiration. Innovation is not created by moderation alone, and many advances in medicine exist because someone was prepared to work harder, think differently and continue when the easier course would have been to conform.

The cost of that intensity is not always visible in the final account of success. Time devoted to discovery is time not spent elsewhere, and a professional life of exceptional concentration may leave less room for family, friendship, leisure and the development of an identity outside medicine. This does not mean that every great innovator has neglected those parts of life, nor that sacrifice inevitably produces vanity. It does mean that an achievement may gradually be asked to carry more psychological weight than the achievement itself. It may have to justify the missed evenings, the strained relationships, the years of uncertainty and the parts of ordinary life that were deferred or surrendered in its pursuit.

Once that happens, recognition may cease to be merely gratifying and become necessary. To be regarded as one important contributor may feel inadequate if the work has become the explanation for everything that was given up to create it. The achievement then has to become singular, and the individual may need to occupy a pedestal proportionate to the sacrifices made. The need is no longer simply to be credited accurately, which is entirely legitimate, but to have the professional legacy confirm that the sacrifices were worthwhile and that the life organised around the work possessed a unique meaning.

This is one of the more uncomfortable shadows cast by medical greatness. A profession built upon empathy, care and service to others can generate lives in which enormous outward energy is devoted to patients and scientific progress, while the emotional meaning of that work turns increasingly inward. The discovery becomes identity, the identity becomes legacy and the legacy becomes the structure through which the person understands his own worth. A challenge to the historical account may then feel like far more than a disagreement over facts; it can feel like a challenge to the value of the life that produced them.

What a mature legacy looks like

Understanding these psychological pressures does not mean that legitimate claims to priority should be surrendered. Medical history can be unjust, and there are circumstances in which a contributor must defend his work against appropriation, neglect or deliberate distortion. The distinction lies between protecting what is genuinely one’s own and needing the achievement to absorb the contributions of everyone else. Developing a procedure into something safe, reproducible and widely usable may be far more consequential than having had the earliest incomplete idea. Naming and systematising a field may transform practice even when some of its component parts already existed, and the person who integrates multiple strands into a coherent clinical method may deserve enormous credit without deserving all of it.

There is no need to claim everything in order to have accomplished something extraordinary. Indeed, the insistence upon claiming everything may weaken the very legacy it is intended to protect, because an expansive claim invites scrutiny while a precise one is more likely to endure. The tragedy is that this often happens to people whose true achievements were already sufficient. No embellishment was required, no predecessor had to be erased and no parallel contributor had to be diminished; the legitimate contribution could have stood perfectly well on its own.

The deepest issue is therefore not historical but psychological. Can a person receive immense credit without requiring exclusivity, and can an innovator remain proud of a decisive contribution while accepting that others supplied essential foundations? These are difficult questions because achievement does not remove insecurity and may sometimes conceal it. A person may accumulate honours while remaining intensely vulnerable to the suggestion that the defining achievement was not entirely his. Anger can then protect against the more painful fear that sharing credit will lead to being forgotten, and possessiveness becomes an attempt to secure legacy even though in practice it often has the opposite effect.

A pioneer who acknowledges predecessors and collaborators appears larger, not smaller. Generosity signals that the achievement is secure enough to withstand complexity, whereas the refusal to share credit invites closer scrutiny and risks allowing the dispute over ownership to become part of what is remembered. This matters particularly in medicine, where the way discovery is remembered contributes to the moral culture inherited by the next generation. If senior figures model historical generosity, younger doctors learn that credit is not diminished by accuracy and that recognising others does not erase one’s own contribution. If the opposite is modelled, innovation becomes inseparable from possession and scientific history becomes a struggle over territory.

Medicine cannot abolish these aspects of human nature. Doctors do not cease to be vain, frightened or competitive because they have entered a healing profession, and the solemnity of medicine may even make these tendencies harder to recognise because we prefer to believe that noble work ennobles everyone who performs it. It does not. Noble work can coexist with vanity, generosity with possessiveness, brilliance with insecurity and healing with rivalry. Perhaps genuine humility is not modest language or the ritual denial of one’s accomplishments, but the capacity to hold a great achievement, and all the sacrifices that made it possible, without requiring the achievement to justify an entire life or eclipse every other contribution. We all stand on the shoulders of others, even when we climb higher than they did, and acknowledging those shoulders does not weaken a legacy; it is what makes the legacy believable.

Most SMILE surgery is still programmed using broadly generic settings. A familiar cap thickness, a standard optical zone and a conventional residual stromal limit are applied to most patients. That works, but it leaves much of the potential of SMILE unused.

SMILE, or KLEx, is not simply LASIK performed without a flap. Its geometry can be programmed around the individual eye: cap thickness, optical zone, lenticule thickness, centration, stromal preservation and even the pathway for a future enhancement can all be deliberately altered. The difference between basic and advanced SMILE is therefore not the laser; it is the programming.

Start with biomechanics, not residual stromal bed alone

Refractive surgeons have traditionally been trained around residual stromal thickness. In LASIK, approximately 250 µm beneath the flap and ablation has long been used as a conventional minimum, although our own modelling demonstrated years ago that there is no universally safe RST independent of the accuracy and reproducibility of the complete clinical protocol. (1,2)

SMILE changes the biomechanical equation. The anterior 40% of the corneal stroma is its strongest region, while the posterior stroma is substantially weaker. (3,4) LASIK severs these anterior lamellae with the flap side cut, after which the flap contributes relatively little to postoperative tensile strength. SMILE leaves those lamellae intact everywhere except at the small access incision, and there is also evidence of postoperative biomechanical remodelling and partial strength recovery after SMILE. (5,6)

The relevant concept is therefore not simply the posterior residual stromal bed, but the total uncut stroma: the intact cap above the lenticule plus the residual stroma beneath it. This produces an initially counterintuitive result. In LASIK, increasing flap thickness weakens the cornea. In SMILE, increasing cap thickness moves the lenticule deeper while preserving more of the strong anterior stroma. Our mathematical model found postoperative relative tensile strength to decrease by approximately 0.22% per micron of additional LASIK flap thickness, but to increase by approximately 0.08% per micron of additional SMILE cap thickness. (5)

That model also predicted that a SMILE lenticule could be approximately 100 µm thicker than a LASIK ablation and still leave equivalent postoperative corneal tensile strength. (5) This is why SMILE cannot sensibly be assessed by simply importing LASIK residual-bed or PTA rules and treating the posterior stromal thickness as though the intact anterior cap does not exist.

Optical zone is one of the most powerful variables

Perhaps the single most important programming decision for optical quality is the diameter of the optical zone. Spherical aberration induction falls dramatically as the SMILE optical zone is enlarged: in our topographic analyses, the rate of spherical aberration induction per dioptre fell from a regression slope of approximately 0.081 with a 6.0 mm optical zone, to approximately 0.05–0.06 at 6.5 mm, and approximately 0.03 at 7.0 mm. (7)

In LASIK and PRK, increasing the optical zone rapidly consumes more anterior stromal tissue. SMILE’s biomechanical preservation gives considerably more freedom to enlarge the treatment zone without paying the same structural penalty. This allows the optical zone itself to become an important variable in the optimisation of visual quality rather than simply accepting the manufacturer’s default setting. (5,7)

This is particularly valuable in patients with large pupils and in low myopia. A low correction naturally creates a very thin, delicate lenticule, so enlarging the optical zone to 7.0 mm or more increases lenticule thickness, making identification and extraction easier while simultaneously improving optical quality. A thicker SMILE lenticule therefore does not necessarily mean that excessive tissue has been removed; it may reflect a deliberate decision to create a substantially larger and optically superior treatment zone. (18)

The limit is geometric rather than conceptual. The optical zone, transition zone and surgical clearance must all fit within the cap diameter. With an 8.0 mm cap, for example, a 7.5 mm optical zone and 0.1 mm transition zone leave very little peripheral working space in which to identify, pocket and separate the interfaces. Experienced surgeons can safely work with much tighter clearances than would be advisable during the learning curve. (18)

Why SMILE induces so little spherical aberration

Optical zone is only part of the explanation. A substantial component of the postoperative shape change after excimer corneal surgery is biomechanical rather than simply optical: interruption and relaxation of stromal lamellae alter peripheral stromal geometry and consequently central corneal curvature. SMILE avoids the circumferential LASIK flap side cut, leaving the anterior stromal architecture largely intact apart from the approximately 2 mm access incision. (5,7)

This helps explain why a relatively simple SMILE lenticule profile can induce similar or fewer higher-order aberrations than sophisticated aspheric excimer profiles for a comparable treatment diameter. Comparative clinical studies have indeed demonstrated lower induction of higher-order aberrations and spherical aberration after SMILE than after femtosecond LASIK. (7,8) The cornea is behaving differently because there is less disruption of the anterior stromal architecture.

There is also an epithelial component. The minimum lenticule thickness creates a peripheral stromal step that effectively “trips” epithelial remodelling, producing a peripheral epithelial response while reducing the amount of central epithelial thickening that would otherwise increase positive spherical aberration. The epithelial and biomechanical responses therefore work together, and the ability to programme larger optical zones gives SMILE a further means of suppressing spherical aberration. (11–13,18)

Centration matters, but not infinitely

Our topographic analysis identified a breakpoint at approximately 0.335 mm of total decentration. Below this level the relationship between increasing decentration and induced higher-order aberrations was small; above it, the induction of coma, spherical aberration and total higher-order aberrations increased significantly. (9) This gives centration a clinically meaningful target rather than an abstract demand for perfection.

Because SMILE does not rely on active intraoperative eye tracking, centration is established during docking. We centre using the coaxially sighted corneal light reflex and patient fixation, and where required use marking techniques to control cyclotorsion and alignment in higher astigmatism. Triple-marking techniques have been shown to improve treatment centration and reduce induced coma, spherical aberration and total higher-order aberrations. (10)

The objective is therefore not simply to “dock centrally”. It is to position the effective treatment zone accurately relative to the corneal vertex and keep decentration within the range in which it ceases to have a meaningful optical consequence. (9,10)

The epithelium is part of the optical system

Another frequently overlooked element of SMILE is epithelial remodelling. The epithelium is not simply a passive transparent covering; it changes thickness in response to alterations in the underlying stromal curvature and can mask or amplify stromal shape. We demonstrated this principle extensively with epithelial thickness mapping after excimer surgery, and subsequent studies have confirmed substantial epithelial remodelling after SMILE. (11–13)

This matters particularly when programming low myopia, because thin lenticules can be mechanically difficult to separate and can permit lamellar distortion of the superficial cut from expanding gas generated during the first cut. Increasing both optical zone diameter and minimum lenticule thickness to 20 or 30 µm can make the lenticule easier to identify and handle, while increasing separation between the two interfaces so that the lenticule surfaces are smoother and visual recovery faster. Although this increases the geometric step at the edge, epithelial remodelling smooths the local curvature transition. (13,18)

Again, the programming decision cannot be reduced to a single number. Surgical handling, epithelial biology, optical geometry and biomechanics interact, and the optimal settings depend on understanding all four.

Hyperopic SMILE exposes another advantage

Hyperopic treatment makes the difference between excimer and femtosecond geometry particularly obvious. Hyperopic LASIK removes most tissue in the peripheral cornea, where excimer pulses arrive increasingly obliquely and are affected by projection and reflection losses. The effective optical zone therefore tends to contract, contributing to spherical aberration and refractive regression.

The femtosecond laser does not have the same angle-of-incidence limitation because it delineates the lenticule intrastromally. By combining an appropriate optical zone with a large dedicated transition zone, hyperopic SMILE can produce a substantially broader topographic treatment. In our prospective series, SMILE programmed with a mean 6.37 mm optical zone and 2 mm transition zone produced a larger achieved optical zone than 6.5 mm hyperopic LASIK and one similar to 7.0 mm LASIK. (14,15)

The spherical aberration data followed the same pattern. Mean spherical aberration change was −0.45 ± 0.22 µm after 6.37 mm hyperopic SMILE, compared with −0.69 ± 0.22 µm after 6.5 mm LASIK and −0.50 ± 0.21 µm after 7.0 mm LASIK. (15) This is not simply another way of removing the same amount of tissue; it is a fundamentally different treatment geometry.

Program today’s operation for tomorrow’s enhancement

Advanced SMILE programming also anticipates something that most patients will never need: retreatment. Where anatomy permits, a relatively thick primary cap preserves the option of creating a separate thin LASIK flap above the original SMILE interface years later, and we have published the predictability and safety of this approach. (16)

In our programming protocol, the preferred cap thickness is approximately 130–145 µm when the anatomy permits. This creates sufficient separation for a future thin LASIK flap above the original interface. If tissue constraints make that impossible, we move deliberately to a 100 µm cap so that the original cap can subsequently be converted to a flap using Circle if required. Intermediate depths can offer the worst of both worlds: too superficial to place a new LASIK flap safely above them, yet deeper than necessary for cap-to-flap conversion, effectively consuming stromal tissue that could otherwise remain available for an enhancement. (16–18)

Circle is an effective rescue pathway, but it creates a circumferential side cut and thereby sacrifices part of the biomechanical advantage of the original flapless procedure. (17) The best enhancement strategy therefore begins before the primary operation has even been performed.

The machine should not dictate the treatment

Generic settings make SMILE straightforward to teach and reproduce, but they should not be confused with optimal programming. The advanced surgeon asks a different set of questions: How much anterior stromal strength can I preserve? How large an optical zone can this cornea support? Where should the lenticule sit biomechanically? How much surgical clearance do I need? How accurately must I centre this particular treatment? How will the epithelium remodel? And if this patient needs an enhancement ten years from now, what options am I leaving available?

That is the frontier of SMILE. It is not simply performing lenticule extraction through a smaller incision, but programming the geometry of the operation around the individual eye rather than programming every eye around the default settings of the machine.

References

1. Reinstein DZ, Srivannaboon S, Archer TJ, Silverman RH, Sutton H, Coleman DJ. Probability model of the inaccuracy of residual stromal thickness prediction to reduce the risk of ectasia after LASIK. Part I: Quantifying individual risk. J Refract Surg. 2006;22:851–860. doi:10.3928/1081-597X-20061101-04. (PubMed)

2. Reinstein DZ, Srivannaboon S, Archer TJ, Silverman RH, Sutton H, Coleman DJ. Probability model of the inaccuracy of residual stromal thickness prediction to reduce the risk of ectasia after LASIK. Part II: Quantifying population risk. J Refract Surg. 2006;22:861–870. doi:10.3928/1081-597X-20061101-05. (PubMed)

3. Randleman JB, Dawson DG, Grossniklaus HE, McCarey BE, Edelhauser HF. Depth-dependent cohesive tensile strength in human donor corneas: implications for refractive surgery. J Refract Surg. 2008;24:S85–S89. doi:10.3928/1081597X-20080101-15. (PubMed)

4. Scarcelli G, Pineda R, Yun SH. Brillouin optical microscopy for corneal biomechanics. Invest Ophthalmol Vis Sci. 2012;53:185–190. doi:10.1167/iovs.11-8281. (PubMed)

5. Reinstein DZ, Archer TJ, Randleman JB. Mathematical model to compare the relative tensile strength of the cornea after PRK, LASIK, and small incision lenticule extraction. J Refract Surg. 2013;29:454–460. doi:10.3928/1081597X-20130617-03. (PubMed)

6. Shetty R, Francis M, Shroff R, et al. Corneal biomechanical changes and tissue remodeling after SMILE and LASIK. Invest Ophthalmol Vis Sci. 2017;58:5703–5712. doi:10.1167/iovs.17-22864. (PubMed)

7. Reinstein DZ, Archer TJ, Gobbe M. ReLEx SMILE induces significantly less spherical aberration than wavefront optimised sub-Bowman’s LASIK for any given residual postoperative relative tensile strength. Presented at the XXXII Congress of the European Society of Cataract and Refractive Surgeons; London, 2014. (ESCRS)

8. Lin F, Xu Y, Yang Y. Comparison of the visual results after SMILE and femtosecond laser-assisted LASIK for myopia. J Refract Surg. 2014;30:248–254. doi:10.3928/1081597X-20140320-03. (PubMed)

9. Lee H, Roberts CJ, Arba-Mosquera S, Kang DSY, Reinstein DZ, Kim TI. Relationship between decentration and induced corneal higher-order aberrations following small-incision lenticule extraction procedure. Invest Ophthalmol Vis Sci. 2018;59:2316–2324. doi:10.1167/iovs.17-23451. (Yonsei University)

10. Kang DSY, Lee H, Reinstein DZ, et al. Comparison of the distribution of lenticule decentration following SMILE by subjective patient fixation or triple marking centration. J Refract Surg. 2018;34:446–452. doi:10.3928/1081597X-20180517-02. (PubMed)

11. Reinstein DZ, Archer TJ, Gobbe M. Change in epithelial thickness profile 24 hours and longitudinally for 1 year after myopic LASIK: three-dimensional display with Artemis very high-frequency digital ultrasound. J Refract Surg. 2012;28:195–201. doi:10.3928/1081597X-20120127-02. (PubMed)

12. Reinstein DZ, Archer TJ, Gobbe M. Rate of change of curvature of the corneal stromal surface drives epithelial compensatory changes and remodeling. J Refract Surg. 2014;30:799–802. doi:10.3928/1081597X-20141113-02. (PubMed)

13. Luft N, Ring MH, Dirisamer M, et al. Corneal epithelial remodeling induced by small incision lenticule extraction (SMILE). Invest Ophthalmol Vis Sci. 2016;57:OCT176–OCT183. doi:10.1167/iovs.15-18879. (JKU & KUK Research Portal)

14. Reinstein DZ, Pradhan KR, Carp GI, et al. Small incision lenticule extraction (SMILE) for hyperopia: optical zone centration. J Refract Surg. 2017;33:150–156. doi:10.3928/1081597X-20161220-01. (PubMed)

15. Reinstein DZ, Pradhan KR, Carp GI, et al. Small incision lenticule extraction (SMILE) for hyperopia: optical zone diameter and spherical aberration induction. J Refract Surg. 2017;33:370–376. doi:10.3928/1081597X-20170331-01. (Healio Journals)

16. Reinstein DZ, Carp GI, Archer TJ, Vida RS. Outcomes of re-treatment by LASIK after SMILE. J Refract Surg. 2018;34:578–588. doi:10.3928/1081597X-20180717-02. (PubMed)

17. Siedlecki J, Luft N, Mayer WJ, et al. CIRCLE enhancement after myopic SMILE. J Refract Surg. 2018;34:304–309. doi:10.3928/1081597X-20180308-02. (PubMed)

18. Reinstein DZ, Archer TJ, Carp GI. The Surgeon’s Guide to SMILE: Small Incision Lenticule Extraction. Thorofare, NJ: SLACK Incorporated; 2018. (Google Books)

Financial disclosure: Dan Z. Reinstein is a consultant for Carl Zeiss Meditec and CSO Italia and has a proprietary interest in the Artemis Insight 100 technology and through patents administered by the Cornell Center for Technology Enterprise and Commercialization.

This watercolour was painted for me by Chick Corea as a personal thank you after I performed his PRESBYOND Laser Blended Vision surgery. Chick wasn’t someone who explained profound experiences with lots of words. He expressed them through music, intuition and, in this case, through paint. He simply handed me this watercolour. I have always felt that he wasn’t painting what he saw. He was painting what he experienced. That is why it remains the most honest depiction I have ever seen of what this surgery really gives back.

At the bottom of the painting sits a red, blunted eye within a soft, almost childlike face. It doesn’t appear blind, only diminished. The expression feels subdued, as though vision has quietly lost its vitality rather than suddenly failed. To me, this is presbyopia. Not simply the inability to read small print, but the gradual narrowing of a person’s effortless engagement with the visual world. There is vulnerability in this figure, a subtle sadness, as though the eye has become trapped within the limitations of age.

As the painting rises, everything changes. A second eye emerges high above within a bright triangular form that feels simultaneously like a refractive prism, a crown and a third eye. This is no longer simply an eye that looks. It is an eye that sees. The geometry becomes more coherent, the colours more vibrant, the composition more expansive. It feels like the moment after successful PRESBYOND, when near, intermediate and distance vision stop competing with one another and become a single effortless visual experience. It is not merely sharper vision. It is the return of visual freedom.

The entire composition moves upwards, from functional limitation towards perceptual wholeness. The muted eye becomes the seeing eye that sees all. The emotional landscape of presbyopia gives way to one that is richer, freer and more multidimensional. It is both a deeply personal thank you and a visual poem about recovering the fluidity of vision. Chick didn’t describe the experience. He translated it into colour, shape and symbol.

I was reluctant to share this painting after Chick passed away because, like everyone, I was shocked by how suddenly we lost him. He possessed a rare combination of genius, humility and empathy. He had an extraordinary ability to understand people without needing many words, and perhaps that is why this painting has always meant so much to me. Coming from one of the greatest improvising musicians who has ever lived, it feels less like a picture and more like another composition. Only this time, instead of music, he was improvising with vision.

#ChickCorea
#PRESBYOND
#LaserBlendedVision
#Presbyopia
#LaserEyeSurgery
#ReturnToForever

There is a particular sentence I have heard thousands of times in consultation: “I could never have laser eye surgery. I can’t bear anything touching my eyes.” Often the patient has already tested this fear in another setting. They will say, “I even tried contact lenses, but there was no way I could get them in or out.” Sometimes an optometrist has spent hours trying to teach them how to handle lenses, only for the patient to leave feeling embarrassed, defeated, and convinced that if they cannot manage contact lenses, they could never possibly manage laser eye surgery. But those are not the same thing. Struggling with contact lenses tells me that the eye is highly defended and that the patient may need careful handling. It does not, by itself, tell me that surgery is impossible.

The truth is that almost everyone is squeamish about their eyes. The eye is one of the most protected organs in the body, and the reflex to blink, pull away, flinch or guard the eye is not weakness. It is biology. So when a patient tells me they are frightened of laser eye surgery, or scared of LASIK, or scared of SMILE, or worried that they cannot even put drops in, I do not regard that as unusual. It is one of the most normal starting points in refractive surgery. There is no such thing as a patient who has no anxiety. There are only different levels of anxiety, from mild nervousness to something so extreme that it becomes a true phobia.

John, not his real name, was probably the most extreme example I have ever treated. He was not an anxious man in any ordinary sense. Quite the opposite. He was articulate, successful, internationally experienced and very robust. He had worked in parts of the world where most people would feel anything but calm, including Congo, where he had been involved in building hospitals, schools and training infrastructure in places where the civil war had left almost nothing functioning. He could describe, quite calmly, the realities of doing business in difficult regions, of rebuilding local structures, of trying to employ and train local workers when even literacy in French or English could not be assumed, and of thinking about warning signs through pictograms because safety had to begin at the most basic level. This was not a fragile person. This was not someone who avoided risk in life. But eyes were different.

His eye phobia was extraordinary. When he stayed in a hotel, he would move the bedside table away from the bed because he was afraid that he might turn over in his sleep and hit his eye on the corner. Think about that for a moment. This was not simply someone saying, “I don’t like eye drops.” This was a whole protective system built around the possibility of eye injury, even during sleep, even from a bedside table. The fear had become spatial. It had entered ordinary life. The room itself had to be reorganised around the eye.

The extent of it became even clearer in consultation. John told me that even if we somehow managed to get him through the surgery, he did not think he would be able to put drops in his eyes afterwards. So we experimented. I handed him a bottle of artificial tears and asked him to put a drop in his eye. He took the top off the bottle, began to raise it towards his face, and after only a few inches of movement he went into a full panic attack. He was hyperventilating, in a cold sweat, with dilated pupils. He had not even reached the eye. The threat was not the drop itself. It was the approach. His nervous system had already decided that the eye was in danger.

We later pieced together what was probably the origin of the phobia. At around the age of two, John had apparently been held down in an emergency room while a foreign body was removed from his eye. At that age, a child cannot understand the medical logic of what is happening. He cannot think, “These adults are helping me.” He cannot distinguish treatment from assault in the way an adult can. What the body stores is much more primitive: being restrained, not being able to escape, adults coming close, pain or fear around the eye, and the overwhelming sense that the eye is in danger. Many phobias are like this. They are not stored as tidy autobiographical memories. They are stored as bodily alarms.

That is why rational reassurance alone often does not work. You can tell someone that the procedure is safe. You can tell them that we do this all the time. You can tell them that there is nothing to worry about. But if the phobia is sitting in the nervous system at the level of a two-year-old child being held down, the adult part of the mind may understand the explanation while the body still says no. That was John. He could talk about the fear intelligently. He could even laugh about it. But the alarm was still there.

And yet John had laser eye surgery. Not only did he have laser eye surgery, he did brilliantly. Fifteen years later, I saw him again, and his eyes were still remarkably stable. His distance vision remained excellent. The only thing beginning to change was the normal age-related weakening of near vision, which is exactly what one would expect after 15 years. He remembered that I had warned him this would eventually happen. The surgery itself had done what it was supposed to do. The phobia had not prevented the outcome.

The reason John could have surgery was not because the phobia disappeared. It was because we knew how to get him through it. That distinction is important. We did not need to turn him into a person who loved having things near his eyes. We did not need him to become brave in some heroic sense. We needed to manage the phobia so that it did not control the experience. That is where expertise matters. It is also where many patients misunderstand what expert refractive surgery really involves.

For the patient, the procedure itself is best treated almost as a black box. I do not mean that patients should be uninformed. They should understand the benefits, risks, alternatives and recovery. They should be properly consented. They should know what matters medically. But for an anxious or phobic patient, repeatedly describing the mechanics of the procedure is often the least helpful thing one can do. The anxious mind takes every detail and turns it into a film, then rehearses that film again and again until the imagined event becomes more frightening than the real one. The aim is not to overload the patient with mechanics. The aim is to consent them properly, explain what they need to know, and then guide them through the day in a way that keeps the fear from taking command.

That is why the surgical day is deliberately choreographed. The laser treatment may take less than 10 minutes, but the patient is with us for around two hours. That is not inefficiency. It is part of the care. There is a soft landing before the operating room. The pace is controlled. The patient is not rushed from reception into theatre as though they are on a conveyor belt. The surroundings, the timing, the order of events, the way the team speaks, the tone of the room, the sense that everyone knows exactly what is happening, all of this is designed to settle the nervous system before the procedure ever begins.

This is not only for the obviously anxious patient. It is for every patient. Some people show their anxiety. Some cover it with jokes. Some become over-talkative. Some go quiet. Some look completely calm and then tell you afterwards that they were terrified. There is no useful distinction between “anxious patients” and “normal patients”, because anxiety is normal. The only question is how much of it is present and how skilfully the team manages it.

At London Vision Clinic, and among surgeons trained in our methods, this is part of the surgery. It is not an optional extra. It is not something we do only when someone is visibly panicking. The language, the timing, the rhythm, the way the patient is moved through the day, the way attention is directed, the way expectations are created and then fulfilled, the way the patient is kept connected to the surgeon’s voice rather than to their own fear response, all of this is deliberately thought out. The procedure may be technical, but the experience is psychological.

That is what we do at London Vision Clinic, and that is what we teach surgeons around the world. I can lecture to a room full of surgeons who, between them, have placed a speculum in the eye tens of thousands of times, and I will still spend 30 minutes teaching them how to put one in without the patient even realising it is there. To the surgeon, it may seem like a small technical step. To the patient with eye phobia, it may be the whole mountain. I have had a lifelong interest in magic, and in a sense this is not entirely unrelated. Magic is not just about the move itself. It is about patter, timing, misdirection and guiding attention so that the audience experiences something differently from what is actually happening. Surgery is not magic, of course, but the same human principles apply. The difference between the patient coping and not coping can lie in tiny details of timing, language, rhythm, touch, attention and expectation.

That is where the word hypnosis becomes useful, although it is also a word that can easily be misunderstood. We use hypnosis-based communication techniques with every patient, not just with the obviously anxious ones. This is not theatrical hypnosis. It is not swinging watches or making people do strange things on a stage. It is the disciplined use of communication to narrow attention, reduce panic, slow the nervous system, create rhythm and keep the patient connected to the surgeon’s voice rather than to the fear response. In most patients, this is simply part of creating a calm, controlled surgical experience. In John’s case, the same principles had to be taken to their furthest extreme because the phobia was so unusual.

The only major difference was the use of sedative medication. Some practices give sedatives to every patient. That is not our approach. In our practice, only 3.11% of patients receive anxiolytic medication. The reason is not that we are indifferent to anxiety. It is exactly the opposite. The whole environment and protocol are designed to manage anxiety before medication becomes necessary. Most patients can be guided through the experience using preparation, pacing, communication and confidence. John was different. His phobia was so far outside the normal range that the same protocol needed additional pharmacological support.

Even then, it had to be judged carefully. Before surgery, we had to establish whether medication would actually get him below the panic threshold, rather than simply assume that an ordinary dose would be enough. That was how we discovered one of the most memorable details of the whole story: after taking enough lorazepam to sedate most people quite substantially, he was still able to go on to work, with the only reported effect being that his secretary thought he was unusually mellow that day. That was not the point of the exercise, of course. The point was that we needed to know what would be required to make surgery possible for someone whose fear response was so far outside the normal range. It tells you both how extreme the phobia was and how high-functioning he remained outside that narrow trigger.

The important point is that we did not fight the phobia. We worked around it, through it and past it. We structured the experience so that John did not have to carry the whole psychological burden himself. The team knew what was happening. The communication was planned. The medication was appropriate. The environment was controlled. He was not shamed, rushed or treated as difficult. He was treated as a patient with a very specific nervous-system response that required expert handling.

Most patients are not John. Most people who say they are scared of laser eye surgery are nowhere near that extreme. They may be squeamish. They may hate drops. They may be worried they will blink. They may feel faint at the thought of someone coming near the eye. But they are not moving hotel furniture away from the bed because of a fear of eye injury during sleep, and they are not going into a panic attack while trying to approach their own eye with artificial tears. If John could be treated successfully, many patients who assume they are “too scared for laser eye surgery” are probably much more manageable than they think.

Of course, fear is not the same as medical suitability. Not everyone should have laser eye surgery. The decision still depends on proper examination, corneal imaging, prescription, age, ocular surface health, visual needs and long-term safety. That is non-negotiable. But once the eyes are suitable, the fact that the patient is nervous, squeamish or even phobic does not automatically exclude them. It simply means the patient needs to be looked after by people who understand that refractive surgery is not only optical and surgical. It is psychological.

This is why I am careful when patients say, “I could never do it.” Very often what they really mean is, “I cannot imagine how I would get through it.” That is a different statement. The answer to that is not, “Don’t worry.” The answer is, “We know how to manage this.” There is a huge difference between reassurance and expertise. Reassurance asks the patient to believe. Expertise gives the patient less to fear.

John’s story stayed with me because it showed the outer edge of what is possible. He was one of the most eye-phobic patients I have ever treated. His fear probably began with being held down as a small child while a foreign body was removed from his eye. It grew into a lifelong protective response around anything that might touch, approach or injure the eye. It was severe enough to alter how he arranged a hotel room. It was severe enough to trigger panic when he tried to put in a simple lubricating drop. And yet, with the right medication, the right surgical communication, the right team and the right management, he had laser eye surgery and did extremely well.

So if you are searching for “scared of LASIK”, “too scared for laser eye surgery”, “eye phobia laser eye surgery”, “I can’t touch my eyes”, “scared of eye drops”, “I could never wear contact lenses” or “will I panic during laser eye surgery”, the message is not that your fear is silly. It may be very real. It may even have a history. The message is that fear itself is not the deciding factor.

The deciding factors are whether your eyes are medically suitable and whether the people looking after you are expert enough to manage the whole person, not just the prescription.

Laser eye surgery is technical. Expert care is human. John needed both, and that is why we were able to get him through.

One of the more revealing things in refractive surgery is how sometimes a surgeon’s opinion about what is safe or possible reflects the limits of their own training, technology, or experience rather than the limits of the procedure itself.

Hyperopic LASIK is a good example. For years, many surgeons have repeated the same objections. Hyperopic LASIK regresses. It is difficult to centre. It induces aberrations. It steepens the cornea too much. It can cause apical syndrome. Therefore, the argument goes, hyperopic patients should often be moved away from the cornea and towards lens surgery.

The difficulty is that many of these concerns originate from an earlier era. They are based on older laser platforms, smaller optical zones, inadequate transition zones, pupil-centred treatments, and a time before epithelial mapping allowed us to understand what was really happening in the cornea after hyperopic treatment. They do not necessarily reflect what can be achieved with modern platforms, modern centration methods, modern transition-zone design, and detailed epithelial thickness analysis.

This distinction matters because patients are sometimes being directed towards intraocular surgery not because their cornea is unsuitable, but because the surgeon they have seen does not have the equipment, the experience, or the conceptual framework to treat the cornea confidently and safely.

Hyperopic corneal surgery has been shaped by three long-standing concerns: regression, centration and excessive steepening. Each of these concerns had a rational origin. Early hyperopic treatments did regress. Poor centration could produce poor quality of vision. Excessive steepening with inadequate transition-zone design could create epithelial breakdown. The question today is not whether those concerns once existed. The question is whether advances in optical-zone design, transition-zone design, vertex centration and epithelial mapping have fundamentally changed the risk profile.

The first concern is regression. It is true that early hyperopic laser treatments regressed badly. That was not because the cornea is inherently unsuitable for hyperopic correction. It was because the ablation profiles were primitive. The optical zones were too small and the transition zones were poorly designed. Once the optical zone and transition zone are understood, the results change dramatically. In our published series of more than 1300 hyperopic LASIK eyes treated up to +6.50 D, 81% of eyes with the potential for 20/20 achieved 20/20 or better, with only 0.6% losing two lines, and stability from three months to one year was 0.02 D (1). In our high hyperopia series, between +4.00 and +7.00 D, 76% achieved 20/20 or better, with 0.4% losing two lines, and stability from one year to two years was 0.09 D (2).

The second concern is centration. Hyperopic ablations are unforgiving if they are centred incorrectly. But the answer was not to abandon hyperopic LASIK. The answer was to centre correctly. The ablation should be centred on the coaxially sighted corneal light reflex, which approximates the visual axis, rather than simply on the entrance pupil centre. We studied this by comparing eyes with small and large angle kappa, all treated using vertex centration. If pupil centration were correct, the large angle kappa group should have done worse. It did not. The outcomes were similar, supporting vertex centration and arguing against the pupil-centre hypothesis (3).

The third concern is steepening. Surgeons often talk as if a post-operative K value above 49 or 50 D is automatically dangerous. That is too simplistic. What matters is not keratometry alone, but epithelial behaviour. A cornea with a relatively modest K reading may already have dangerously thin central epithelium, whereas a steeper cornea may have ample epithelial reserve. Hyperopic LASIK creates a predictable epithelial pattern, with epithelial thickening in the peripheral trough and relative thinning centrally. If you do not measure epithelial thickness, you are partly blind to the real wound-healing state of the cornea (4).

This is where epithelial mapping changed the discussion. It allowed us to see that the risk of breakdown is related to the rate of change of curvature and the epithelial response, not simply to a keratometry number. A cornea with a SimK of 41.5 D and a thinnest epithelium of 26 microns may be more concerning than a cornea with a SimK of 50 D and a thinnest epithelium of 44 microns. Without epithelial mapping, a surgeon may make the wrong decision in both directions: treating a dangerous eye or rejecting a safe one (4).

This is why the arrival of hyperopic SMILE should not be misunderstood. Hyperopic SMILE is not a shortcut past the principles established in hyperopic LASIK. It is an extension of the same knowledge. If you do not understand optical zone, transition zone, centration and epithelial dynamics in hyperopic LASIK, you should not assume that hyperopic SMILE suddenly makes hyperopic corneal treatment simple.

The early hyperopic SMILE work built directly on this history. The lenticule geometry had to be redesigned. The transition zone had to be understood. The procedure had to be centred properly. In the earlier Nepal studies, we showed that hyperopic SMILE could achieve centration equivalent to LASIK and myopic SMILE (5), and that the topographic optical zone could actually be larger with a 6.3 mm SMILE optical zone than with larger programmed hyperopic LASIK zones (6). This was initially surprising, but it makes sense when you remember that, in lenticule extraction, the transition zone is what is physically cut. In excimer laser surgery, the intended transition zone can be degraded by projection effects and time-dependent limitations of the ablation process.

The multicentre hyperopic SMILE study then showed that the concept was clinically viable. The study included 374 eyes, with hyperopic sphere up to +6.00 D, cylinder up to +5.00 D, and maximum hyperopic meridian up to +7.00 D. At 12 months, 93% of eyes were within ±1.00 D and 81% within ±0.50 D of target (7). The results were similar to those reported for modern hyperopic femto-LASIK (1,2). The principal new issue was interface haze, which appears to require a more PRK-like steroid regimen rather than the shorter steroid course commonly used after myopic SMILE (7).

That is not a failure of the concept. It is how refractive surgery evolves. Myopic SMILE also took years of optimisation involving energy settings, spot spacing, centration, cyclotorsion control, nomograms, dissection technique, enhancement strategies and workflow. Hyperopic SMILE is now at the beginning of a similar process.

The broader point is that refractive surgery is full of inherited beliefs. Some were once entirely correct. Some were partly correct under older technology. Some have simply never been revisited. Yet they persist because they are easy to repeat and sound cautious. A surgeon may genuinely believe they are protecting patients when, in reality, they are relying on assumptions formed many years earlier.

This matters most for patients. A hyperopic patient may be told that corneal laser surgery is unsuitable and that lens exchange is the safer or more permanent option. Sometimes that is true. But sometimes it is not. Sometimes the cornea is being abandoned too early because the surgeon is relying on older assumptions, older equipment, incomplete diagnostics, or a treatment philosophy that has not fully incorporated what modern refractive surgery can achieve.

Modern refractive surgery is not about being aggressive. It is about being precise. It is about knowing when the cornea can be treated, when it should not be treated, and what measurements are needed to tell the difference. For hyperopia, that means understanding the historical limitations without remaining constrained by them.

The cornea was never the problem. The problem was treating it without the right optical zone, the right transition zone, the right centration, the right diagnostics, and the right understanding.

DISCLOSURE

Dan Reinstein is a consultant for Carl Zeiss Meditec AG, CSO Italia and BVI Medical, and has a proprietary interest in the Artemis Insight 100 technology through patents administered by the Cornell Center for Technology Enterprise and Commercialization.

REFERENCES

1. Reinstein DZ, Carp GI, Archer TJ, Day AC, Vida RS. Outcomes for Hyperopic LASIK With the MEL 90 Excimer Laser. J Refract Surg. 2018;34(12):799–808.

2. Reinstein DZ, Carp GI, Archer TJ, Buick T, Gobbe M, Rowe EL, Jukic M, Brandon E, Moore J, Moore T. LASIK for the Correction of High Hyperopic Astigmatism With Epithelial Thickness Monitoring. J Refract Surg. 2017;33(5):314–321.

3. Reinstein DZ, Gobbe M, Archer TJ. Coaxially Sighted Corneal Light Reflex Versus Entrance Pupil Center Centration of Moderate to High Hyperopic Corneal Ablations in Eyes With Small and Large Angle Kappa. J Refract Surg. 2013;29(8):518–525.

4. Reinstein DZ, Archer TJ, Gobbe M, Silverman RH, Coleman DJ. Epithelial Thickness After Hyperopic LASIK: Three-dimensional Display With Artemis Very High-frequency Digital Ultrasound. J Refract Surg. 2010;26(8):555–564.

5. Reinstein DZ, Pradhan KR, Carp GI, Archer TJ, Gobbe M, Sekundo W, Khan R, Citron K, Dhungana P. Small Incision Lenticule Extraction for Hyperopia: Optical Zone Centration. J Refract Surg. 2017;33(3):150–156.

6. Reinstein DZ, Pradhan KR, Carp GI, Archer TJ, Gobbe M, Sekundo W, Khan R, Dhungana P. Small Incision Lenticule Extraction for Hyperopia: Optical Zone Diameter and Spherical Aberration Induction. J Refract Surg. 2017;33(6):370–376.

7. Reinstein DZ, Archer TJ, Pradhan KR, Blum M, Cochener B, Ganesh S, Sekundo W, Stodulka P, Wang Y, Zhou X, et al. SMILE for Hyperopia With and Without Astigmatism: Results of a Prospective Multicenter 12-Month Study. J Refract Surg. 2022.

I was recently sitting in a lecture at a top-level key opinion leaders conference listening to a talk and a discussion about ICL sizing. Much of what was being said was reasonable. The modern EVO ICL is a much more forgiving lens than the earlier generations. Millions of patients have had successful outcomes. The safety profile is excellent. Surgeons around the world are achieving good results using a variety of different sizing methods. I do not dispute any of that. In fact, the success of the ICL is precisely what makes the discussion so interesting.

What caught my attention was a comment that the company was pleased to see surgeons and researchers continuing to work on the sizing problem. It was not a controversial statement. If anything, it was intended as a positive one. Yet as I listened, I found myself returning to a question I have been asking in one form or another for more than twenty-five years. If the lens is going to sit behind the iris, why is measuring the space behind the iris not central to choosing the size of the lens?

The ICL remains one of my favourite procedures in refractive surgery. For the right patient it is an elegant solution. The natural lens remains inside the eye. No corneal tissue is removed. The optics can be excellent. If I were not suitable for laser eye surgery and had suitable anatomy, I would have no hesitation in considering an ICL myself. Precisely because I think so highly of the procedure, I have always been puzzled by the industry’s attitude to sizing.

Most patients assume that before a lens is implanted behind the non-transparent iris, the surgeon measures the space where that lens is going to sit. The assumption seems so obvious that people are often surprised when they learn that the answer is less transparent. For much of the history of the procedure, surgeons have used measurements taken from the front of the eye and various nomograms to estimate the dimensions of a hidden space behind the iris. Those methods can work remarkably well, and millions of successful procedures prove that. But there is a difference between a method that works and a method that directly measures the anatomy you are trying to understand.

A recent patient consultation brought this issue into sharp focus. They had already been evaluated elsewhere and had quite reasonably been advised that an ICL was likely to be the best solution for their vision. The issue was not whether the procedure was appropriate. It was. The issue was uncertainty. They had been told that if the chosen lens size proved unsuitable it could be exchanged. Again, that is a perfectly accepted approach and one that many excellent surgeons have used for years. What struck me was not the recommendation itself, but their reaction to it. They wanted to know whether there was a way of reducing that uncertainty before surgery. They wanted to know whether the anatomy behind the iris could be measured directly rather than inferred indirectly. From their perspective, it seemed an obvious question.

The more I thought about that consultation afterwards, the more I realised that what bothered me was not really the question of sizing itself. It was the difference between the conversations that happen in conference rooms and the conversations that happen in consultation rooms.

At scientific meetings, discussions about ICL sizing often revolve around workflow, practicality, cost, implementation, scalability and whether a particular approach is worth the additional effort. Those are legitimate considerations. Any surgeon running a busy clinic understands them. Any company developing a product understands them. Any healthcare system understands them. Patients, however, do not think that way. Patients are not trying to optimise a clinic. They are not trying to optimise a business. They are not trying to optimise a workflow. They are trying to optimise the safety and outcome for their own eyes.

If a more direct measurement exists, and if that measurement can reduce uncertainty, patients tend to assume it should simply be used. They do not naturally ask whether it slows down clinic flow, requires additional equipment, increases cost, creates regulatory burden or makes adoption more difficult. They assume that if a surgeon can know more before surgery, then knowing more is preferable to knowing less. That difference in perspective is rarely discussed openly, yet it sits at the centre of the entire sizing debate.

Many surgeons are not doing anything unusual or outside accepted practice by using conventional sizing methods, and many achieve excellent outcomes. The modern EVO lens is extraordinarily forgiving. That is one of the reasons it has become so successful. But the success of the lens has also had an unintended consequence. As I have said for years, the success of the lens has protected the industry from having to solve the sizing problem completely. Had exchange rates remained high, had poorly sized lenses regularly caused major clinical problems, the industry would almost certainly have attacked the issue aggressively. Research budgets would have appeared. Development programmes would have followed. Management teams would have demanded solutions. Instead, the lens became so successful that the remaining uncertainty became commercially and clinically tolerable.

I do not mean that cynically. It is simply how successful organisations often behave. Every company has finite resources. Every development programme competes with another. When a product is performing exceptionally well, the urgency to solve the remaining imperfections naturally diminishes. One does not have to invoke bad intentions to explain it. Human nature is usually sufficient.

What I still find surprising, based on multiple interactions over the years, is that the company most closely associated with the ICL never struck me as particularly interested in owning the solution. Over the years, researchers explored sizing. Independent surgeons explored sizing. Imaging companies explored sizing. Yet the dominant lens manufacturer appeared content to allow multiple sizing approaches to coexist under the umbrella of surgeon preference. Listening recently to the suggestion that it was encouraging to see others continuing to work on the problem, I found myself wondering once again why the burden of that innovation had been left largely to others. Why this company would not want to own and control the safety profile of it’s product.

If I were a patient, I think I would assume that the company manufacturing the lens would want to lead every effort to improve the way that lens is selected, sized and implanted. I would assume that reducing uncertainty would be a strategic priority. I would assume that if there was a better way to understand the anatomy where the lens sits, the manufacturer would want to own that knowledge rather than leave it to individual surgeons and imaging companies to develop. Perhaps that assumption is naïve. Perhaps there are practical realities that make the situation more complicated. Yet I suspect many patients would share it.

I should probably say something personal at this point. I never set out to be in the imaging business. I am a surgeon. My interest has always been the clinical problem, not the machine. If tomorrow someone developed a simpler, faster, cheaper, completely non-contact technology that could measure the relevant anatomy with equal accuracy, I would switch immediately. My interest has never been ultrasound or any particular device. My interest is reducing uncertainty before making an irreversible decision inside a patient’s eye.

That is why this discussion continues to irk me. It is not really about ultrasound. It is not really about a particular diagnostics company. It is about what happens when a technology becomes so successful that the remaining opportunities for improvement no longer feel urgent. The danger is not that innovation stops. The danger is that innovation becomes somebody else's responsibility, while the patient remains largely unaware of what is really going on behind the white coat and the manufacturer's glossy marketing.

The ICL is one of the finest technologies in refractive surgery. Precisely because it is so good, it deserves the best possible understanding of the anatomy in which it sits. The question that stayed with me after that lecture was not whether the modern ICL is safe. The evidence for that is overwhelming. The question was why the company that had the most to gain from solving sizing never seemed to feel the same urgency about the problem as the surgeons who were implanting the lenses. After more than twenty-five years, I still find that difficult to answer.

^{Disclosure: I am a consultant for Carl Zeiss Meditec (Jena, Germany) and CSO Italia (Florence, Italy). I also have a proprietary interest in the Artemis Insight 100 technology (ArcScan Inc, Golden, Colorado) through patents administered by the Cornell Center for Technology Licensing, Ithaca, New York.}

The safest surgeon is not necessarily the surgeon with the most original technique, the greatest confidence, or the strongest personal belief in the way they operate. Safety in surgery comes from something more disciplined than that: a surgeon working within a system that is standardised enough to be measured, but intelligent enough to keep improving when the standard being followed is shown to be suboptimal.

I was sitting on a panel that was supposed to be about mentorship in surgery when the discussion drifted somewhere unexpected. We had been talking about how young surgeons learn, how fellowship programmes have evolved, and how dramatically access to information has changed during the course of a single professional lifetime. One speaker observed that today’s trainees can watch surgical videos from around the world before breakfast. Another pointed out that what was once learned through years of observation in operating theatres can now be accessed instantly on a phone.

As I listened, it struck me that we may have reached a point where information itself is no longer the scarce commodity. When I was training, if somebody had developed a new technique or solved a difficult problem, you often had to travel to see it. You attended the meeting, visited the clinic, stood in the operating theatre and watched. Knowledge moved slowly because people moved slowly. Today knowledge moves instantly. The difficulty facing younger surgeons is not finding information. It is deciding which information deserves to be trusted, which variation represents genuine progress, and which is simply somebody’s personal preference dressed up as expertise.

That was where the conversation turned towards standardisation, and I could feel the familiar discomfort that the word creates. Surgeons are not naturally drawn to standardisation. We are selected for independence. We are problem-solvers by temperament. Most of us entered surgery because we enjoy making decisions, taking responsibility and finding solutions. Those qualities are valuable. They are also precisely the qualities that can make standardisation feel restrictive, as though it somehow limits judgement rather than supports it.

One of the panellists quite reasonably pointed out that there are many ways to skin a cat. Another noted that some of the greatest advances in surgery have come from individuals who refused to accept the established way of doing things. I agreed with both observations. If everyone simply followed the accepted standard forever, phacoemulsification would never have evolved. LASIK would never have evolved. SMILE would never have evolved. Much of what we now regard as routine began as somebody questioning accepted practice.

The longer I have spent in surgery, however, the more convinced I have become that we often misunderstand what a standard actually is.

A standard is not a commandment. It is not a monument to the person who invented it. It is not an attempt to stop progress. A standard is simply the current best shared understanding of how something should be done, based on the accumulated experience of thousands of surgeons and millions of procedures. The critical word there is “shared”. Without that shared starting point, it becomes extraordinarily difficult for a profession to learn collectively.

The example I used during the discussion came from aviation because it remains one of the clearest illustrations. If somebody is learning to fly a Boeing 787, there is no stage of training where the instructor encourages them to start thinking independently by ignoring the standard operating procedures. Nobody regards that as creativity. Nobody regards it as maturity. The pilot learns the standard first. Judgement develops within that framework, not instead of it.

In surgery, by contrast, independence can sometimes become permission to improvise before the fundamentals are secure. That tendency is understandable because surgeons are often rewarded for individuality. We celebrate innovation. We admire originality. We are naturally attracted to people who challenge convention. Yet those same instincts can sometimes make us resistant to the idea that the profession might benefit from a common framework.

I was reminded of this when thinking back to the early years of phacoemulsification. When I began performing phaco in the early 1990s, the field was still relatively disorganised. Some surgeons were still performing extracapsular cataract extraction. Others were using amounts of ultrasound energy that would seem extraordinary today. There were enormous variations in technique, instrumentation and philosophy. Over time, however, certain approaches survived because they consistently produced better outcomes.

Today, nobody seriously argues that a dense cataract should be emulsified in one piece when it can be divided, chopped or cracked into smaller segments. That discussion has largely disappeared, not because surgeons became less creative, but because the evidence accumulated to the point where a better approach became obvious. What began as innovation eventually became standard practice.

That process fascinates me because it demonstrates that standards are not imposed from above. The best standards emerge because a field learns. Surgeons try things. Complications occur. Outcomes are measured. Ideas survive or disappear. Over time, certain questions stop being matters of personal style because the answer becomes increasingly clear.

The same principle applies to SMILE. During the panel discussion I mentioned that I had been at the rock face of SMILE complications. Some of those complications were my own. That is simply the reality of being involved in the development of a new procedure. When we wrote the SMILE textbook, we devoted 157 pages to complications, mistakes, pitfalls and methods of avoiding them. I was not referring to that as an achievement. I was referring to it as an obligation.

One of the responsibilities of experience is to prevent the next generation from having to learn the same lessons the hard way. If a complication has already occurred, if a mistake has already been made, if a better solution has already been identified, there is little virtue in forcing someone else to rediscover it independently. Experience only becomes valuable when it becomes transferable.

This was the point I was trying to make when the discussion returned to the relationship between standardisation and innovation. These concepts are often presented as though they sit in opposition to one another. In reality, I suspect they depend on one another.

Imagine twenty surgeons replacing a LASIK flap twenty different ways. One surgeon reports a lower complication rate. Has a genuine improvement been discovered? Perhaps. But it becomes difficult to know whether the improvement comes from the change being described or from any number of other differences in the way that surgeon operates. Now imagine those same surgeons all starting from the same high-quality baseline technique. One surgeon modifies a single step and demonstrates a measurable benefit. Suddenly the observation becomes understandable. It can be tested, challenged, repeated and either adopted or discarded.

Without a shared framework, innovation can easily become noise. With a shared framework, innovation becomes transferable.

That is why I found myself correcting the discussion when standardisation was framed as belonging to any individual surgeon. It is not my standardisation or anyone else’s. The goal should never be to create followers of a particular surgeon. The goal is to contribute to something larger than ourselves. The standard should sit above the individual surgeon. It should constantly evolve, constantly improve and constantly invite challenge, but it should remain shared.

After the session I found myself continuing the discussion in the hallway, and a different thought occurred to me. For much of my career I have spent a considerable amount of energy arguing with colleagues about techniques, technologies and assumptions that I believed were incomplete or incorrect. Looking back, I am no longer convinced that persuading established surgeons is always where the greatest impact lies.

The next generation has a remarkable advantage. They do not have decades of habits to defend. They are not heavily invested in decisions made twenty years ago. They can start from a higher baseline than many of us did. Perhaps that is why teaching and mentorship have become increasingly important to me. Not because younger surgeons need more information, but because they need help distinguishing between information, judgement and wisdom.

One of the speakers during the session made the observation that residency was not really about learning procedures. It was about becoming a surgeon. I have found myself thinking about that comment ever since. There is probably more truth in it than we often acknowledge.

For patients, this may sound like an internal debate within the profession, but it has direct relevance to the person considering surgery. Patients often assume that safety comes from finding the most confident surgeon, the most charismatic surgeon, or the surgeon with the most unique personal method. In reality, safety often comes from something much less glamorous. It comes from a surgeon working within a system that has been measured, refined, challenged and improved over many years.

The safest surgeon is not the surgeon who invents a new way of operating every morning. Nor is it the surgeon who blindly follows a protocol simply because it exists. The safest surgeon is the one who understands the difference between a standard and standardisation, who recognises that standards can be optimal or suboptimal, and who is committed to improving them without abandoning the discipline that allows progress to be recognised in the first place.

One of the commonest surprises after laser eye surgery is that the patient can suddenly see beautifully in the distance, but the phone feels strangely difficult. This can happen in a 22-year-old on the first day after LASIK, SMILE or PRK, and it can also happen in a much more consequential way in someone in their late thirties or early forties who has both eyes corrected fully for distance.

The symptom sounds contradictory. The surgery has worked. The distance vision may be spectacular. The patient can read number plates, see leaves on trees, or spot a tiny detail far across the room. Yet when they pick up their phone, the image feels less easy than expected. Some describe it as blur. Others say it is not exactly blurred, but it does not “snap” into focus. Some find themselves instinctively holding the phone further away.

To understand this properly, you have to understand something that most short-sighted people have used all their lives without realising it: myopia is not only a distance-vision problem. It is also a near-vision advantage.

A short-sighted eye is naturally focused too close. That is why the distance is blurred without glasses or contact lenses. But the same optical error that makes the distance blurred may make near vision beautifully clear. A patient who is -3.00 dioptres myopic is, without glasses, naturally focused at about 33 cm.

The reason is simple optics. A dioptre is the reciprocal of distance in metres. One dioptre focuses at one metre. Two dioptres focus at half a metre. Three dioptres focus at one third of a metre, roughly 33 cm. So a -3.00 D myope has a natural point of clear focus at almost exactly the distance of a phone, a book, or a menu.

This is why many myopic patients love taking their glasses off to read. They may have done it for years in bed, on the sofa, or when looking at their phone. It feels effortless because it is effortless. Their myopia is focusing the near object for them.

Accommodation is different. Accommodation is the active focusing mechanism of the eye. The crystalline lens inside the eye changes shape to increase focusing power for near. A young person has a large amount of accommodation, often 8 to 10 dioptres or more. Reading a phone at 33 cm requires about 3 dioptres. So a 22-year-old has far more accommodation than they need.

But after laser eye surgery, the optical starting point changes overnight. The eye that used to be -3.00 D and naturally focused at 33 cm is now focused for distance. That is the purpose of the treatment. The patient no longer has to wear glasses to see across the room or down the street. However, to read a phone at 33 cm, they now have to accommodate approximately 3 dioptres.

A 22-year-old can easily do this. The problem is not lack of focusing power. The problem is that the visual system has suddenly lost the near-vision shortcut it had always used. Yesterday, the myopia focused the phone for free. Today, the focusing system has to do the work.

That is why the day-one complaint in a young patient is real, but usually not worrying. There is also early healing to consider. On the first day after LASIK, SMILE or PRK, the tear film is not yet stable, the corneal surface is still settling, and the optical quality may fluctuate slightly. Accommodation works best when the image is crisp enough for the focusing system to lock onto. If the image is a little variable, the focusing response may feel slower or less comfortable.

If the eye is also slightly long-sighted on day one, the effect is even more obvious. A patient who was -3.00 D before surgery may measure +0.50 D the next morning. That does not mean anything disastrous has happened. Small early shifts are common. But optically it matters. Reading at 33 cm now requires the 3 dioptres for the near distance plus the extra 0.50 dioptres to overcome the temporary hyperopia. The total demand becomes about 3.50 dioptres. A young eye can still do that, but compared with the effortless unaided near vision of a -3.00 D myope, it feels different.

In most young patients, this improves over the following days and weeks. The surface smooths, the tear film stabilises, any small early overcorrection may settle, and the brain recalibrates. The patient gradually stops comparing the new visual system with the old myopic shortcut. They start using accommodation automatically, as an emmetropic person has always done.

That is the relatively simple version of the story.

The more important version occurs in the late thirties and early forties.

This is the patient who has been myopic all their life, perhaps -2.00 D, -3.00 D or -4.00 D, and who has always read comfortably by removing their glasses. They may not yet think of themselves as needing reading glasses. They may not even realise that their accommodation has already started to decline. But it has.

Accommodation does not disappear suddenly at 45. It declines gradually from childhood onwards. In the twenties there is a large reserve. By the late thirties and early forties, there may still be enough accommodation for many tasks, but the reserve is much smaller. The patient may be functioning well only because their myopia is quietly helping them.

This is where standard binocular distance correction can create a very different experience.

If both eyes are corrected fully for distance, the patient may be delighted with distance vision but suddenly unable to read comfortably without effort. They may say, “I could read before surgery and now I can’t.” From their point of view, that is a fair description. They could read before surgery because they removed their glasses and used their myopia. After surgery, the myopia is gone. Both eyes are focused for distance. Now near vision depends on accommodation, and at 40 or 42 there may not be enough accommodation left to make that comfortable all day.

This is not because the laser has damaged the focusing system. The laser has not touched the crystalline lens. It is not because the surgery has caused presbyopia. The presbyopia was already developing. The surgery has simply removed the myopia that was masking it.

This distinction is crucial. A 22-year-old who feels that the phone is odd on day one usually has a temporary adaptation problem. A 42-year-old who has both eyes corrected for distance may have had a permanent optical trade-off created: excellent binocular distance vision, but no preserved strategy for near.

This is one of the reasons PRESBYOND Laser Blended Vision LASIK was developed.

Traditional laser eye surgery corrects both eyes as similarly as possible for distance. That is entirely appropriate for many patients, particularly younger patients with abundant accommodation. But it is not always the best strategy for a myopic patient approaching presbyopia. If you simply remove the myopia from both eyes, you may also remove the patient’s only remaining unaided near-vision mechanism.

PRESBYOND is designed to address this problem. It does not treat both eyes as if the only goal is perfect binocular distance. Instead, it creates a controlled blended vision system. One eye is optimised more for distance, the other slightly more for near, and the laser profile increases depth of focus through controlled spherical aberration. The aim is not crude monovision, where one eye is distance and the other is near with a large gap between them. The aim is a continuous binocular range of vision, allowing distance, intermediate and near to overlap in a way the brain can fuse comfortably.

In practical terms, this means that the patient who is 40, 42 or 45 and myopic does not necessarily have to choose between seeing far away and losing functional near vision. With the right testing, the right ocular dominance assessment, and a properly planned treatment, PRESBYOND can preserve much of the near function that the patient was previously obtaining from their myopia, while still giving them excellent distance vision.

This is also why age alone is not the right way to decide treatment. A 42-year-old myope is not the same as a 22-year-old myope. The refraction may look similar on paper, but the accommodative system is not the same. The younger patient has a huge reserve and will usually adapt to full distance correction. The early-presbyopic patient may be relying on myopia more than they realise. Correcting both eyes fully for distance may solve one problem while creating another.

The key is to identify this before surgery, not afterwards. Patients need to understand that their unaided near vision before surgery is not a magical extra feature that remains automatically once the myopia has been corrected. It exists because of the myopia. Remove the myopia from both eyes and you remove that near focal point.

For some patients, that is completely acceptable. They want the best possible distance vision and are happy to use reading glasses when the time comes. For others, especially those in their late thirties and early forties who have never used reading glasses and still expect to read naturally, it can be a shock.

That shock is avoidable if the optics are explained properly.

The young patient who says on day one, “My distance vision is amazing but my phone feels strange,” usually needs reassurance, healing time and adaptation. The early-presbyopic myope who says, “I used to read without glasses and now I can’t,” may be describing a predictable consequence of having both eyes corrected for distance without a blended vision strategy.

The same optical principle explains both situations: myopia was providing near focus. The difference is that the 22-year-old still has enough accommodation to replace it, whereas the 42-year-old may not.

That is the essential point. Laser eye surgery does not take away accommodation. It changes the optical starting point from which accommodation has to work. In a young patient, that change may feel odd for a short time. In a patient approaching presbyopia, it may reveal a near-vision problem that myopia had been hiding for years.

So when a patient can see a fly on the back of a horse in the distance but struggles with their phone, the question is not simply whether the surgery has worked. The question is what kind of visual system we have created. Have we simply corrected both eyes for distance, or have we planned for the patient’s age, accommodation, binocular tolerance and near-vision needs?

That is where the difference lies. Standard binocular distance correction removes myopia. PRESBYOND is designed to replace the lost near advantage of myopia with a more sophisticated optical blend.

For the right patient, that distinction is everything.

When people search online for laser eye surgery, LASIK, SMILE, PRESBYOND, reading glasses treatment, or the best laser eye surgeon in London, they are usually thinking about a personal decision. They want to know whether they can safely reduce or eliminate their dependence on glasses or contact lenses. They want to understand the risks, the benefits, the alternatives, and whether modern refractive surgery really can provide long-term freedom from visual aids.

That is a reasonable place to start. But it is not the whole story.

Laser eye surgery and refractive surgery are usually discussed as private, elective, consumer choices. In reality, they also belong in a much larger conversation about global eye health, avoidable visual impairment, and the burden of uncorrected refractive error around the world.

This is the point that still has not been fully absorbed by public health thinking.

Uncorrected refractive error is one of the leading causes of visual impairment, avoidable blindness and functional disability globally. When presbyopia is included, the numbers become vastly greater still. In other words, the inability to see clearly without glasses, contact lenses, or some other corrective aid is not a niche inconvenience. It is one of the major unresolved problems in world eye care.

This matters especially because refractive error affects so many younger and working-age people. It affects education, work, confidence, productivity, and independence. It affects not only the individual, but also families, dependants, and communities. As myopia continues to rise globally, the scale of this burden is only going to increase.

And yet, when global strategies for visual impairment are discussed, the answer is still usually framed around spectacles.

Spectacles are essential. They are often the only practical option and they remain a vital part of eye care. But they are not the whole answer. In many parts of the world, spectacles break, are lost, need replacing, or are simply difficult to access and maintain. In some cultures they may still carry stigma. Contact lenses are even less adaptable in many environments because they depend on hygiene, education, regular follow-up, and ongoing cost.

If the goal is truly to reduce the burden of uncorrected refractive error, spectacles and contact lenses alone cannot be the full strategy.

This is where refractive surgery needs to be brought properly into the discussion.

Modern laser eye surgery is no longer a speculative or fringe discipline. LASIK and SMILE are highly developed, extensively studied, and widely performed procedures with excellent outcomes in appropriately selected patients. They offer rapid recovery, stable correction, and a very high degree of patient satisfaction. PRESBYOND and other sophisticated presbyopia treatments have further extended what corneal refractive surgery can achieve, offering many patients the possibility of reducing dependence on reading glasses while preserving useful binocular vision.

These procedures address the same refractive problems that cause so much everyday disability: myopia, hyperopia, astigmatism, and presbyopia. Worldwide, tens of millions of corneal refractive procedures have already been performed. The idea that laser eye surgery is merely cosmetic is outdated.

That description never captured the reality particularly well, but it is now clearly insufficient.

If someone cannot function naturally without an external appliance, whether that means glasses or contact lenses, that is not trivial. It may be common, but common does not mean insignificant. The ability to work, drive, read, care for others, participate in sport, move confidently, and function without continual dependence on a corrective device has real value. A procedure that permanently restores natural functional vision should not be dismissed simply because it has traditionally been delivered in the private sector.

That is why refractive surgery should increasingly be understood not as a luxury for the wealthy, but as a disability-reversal procedure.

This argument is not just theoretical. It has been tested in practice.

30 years ago, I became increasingly struck by the fact that refractive error was one of the great neglected subjects in global blindness prevention. At the time, public health attention seemed focused on cataract, glaucoma, and infectious causes of blindness, while one of the biggest causes of visual disability in the world was being comparatively overlooked. I wrote to the World Health Organization about this. The underlying point was simple: if millions of people are visually impaired because they cannot access or sustain basic optical correction, then refractive error has to be central to any serious strategy on global vision.

That conviction eventually led to practical work in Nepal.

Working with Professor Geoff Tabin, whose contribution to global ophthalmology has been extraordinary, and who founded the Himalayan Cataract Project, now Cure Blindness, we helped establish a refractive surgery model in Nepal designed not as a vanity service, but as part of a broader system of eye care. A central figure in that story was Dr Kishore Pradhan, who trained for a year at London Vision Clinic as my Refractive Surgery Fellow. Our London Vision Clinic co-founder and Managing Director, Craig Engelfried, oversaw the setting up of the unit, including its coordination, logistics, and implementation, as our team led the design, building, and launch of the first refractive surgery unit in Nepal. I then supervised Dr Pradhan’s first 50 procedures in Kathmandu, and my colleague Mr Glenn Carp supervised his second 50 before he went solo. The principle was a cost-recovery approach: to use laser vision correction not only to treat refractive error, but also to help support wider humanitarian ophthalmic care. The project demonstrated that refractive surgery could be integrated into a meaningful public health framework in a lower-resource environment. Over time, the Nepal project became self-funding and self-sustaining, with around 5,000 patients treated. That matters because it showed this was not a short-lived charitable gesture, but a viable model.

Just as importantly, it showed how investment in training and standards can propagate far beyond the original project. Dr Pradhan went on to build an illustrious career, not only expanding refractive surgery at Tilganga, but also innovating within the field and publishing with us, including the first Hyperopic SMILE studies and other surgical advances. He later founded his own institute, Matrika, together with a foundation that performs thousands of cataract operations for patients who otherwise could not afford treatment. He is now a world-renowned refractive surgeon who continues to help develop new techniques and products internationally. In that sense, the Nepal project did not simply create a service. It helped train and launch a surgeon who has gone on to advance the specialty itself.

The work did not stop there.

The Nepal model also proved transferable. In Cusco, Peru, Dr Nathan Henson and Dr Christian Becker established a refractive surgery service at La Fuente Centro de Salud Integral after training with us through the Forefront Refractive Surgery Course in London and using our published Nepal experience as the template. I later spent a week there overseeing their first treatments in July of 2019, and helping guide the start-up of the refractive surgery unit, which was conceived as a mirror image of London Vision Clinic, built on the same emphasis on rigorous diagnostics, disciplined protocols, and surgical standards designed to achieve exceptionally low complication rates. As in Nepal, the purpose was not simply to deliver refractive surgery, but to create a sustainable cost-recovery model that could help fund wider humanitarian refractive and ophthalmic care.

And the work continued.

For 2 years, we trained Dr. Daniel Gatineh in refractive surgery both at the London Vision Clinic and through the Ulster University distance learning Post Graduate Diploma in Cataract and Refractive Surgery which I initiated in 2015. curated and through and in July 2025, supervised the opening of the first refractive surgery centre in Ethiopia. The Biruh Vision clinic in Addis Ababa We trained Dr Daniel Gatineh at London Vision Clinic, and the Addis centre is now established and operational. That continuity matters. This is not about dropping equipment into a country and walking away. It is about training, standards, infrastructure, and creating systems that can endure.

That is where refractive surgery becomes especially interesting from a global eye health perspective.

A successful refractive procedure is fundamentally different from an optical aid that needs to be worn, maintained, replaced, and continuously afforded. Even in high-income countries, laser eye surgery is often economically rational over time compared with the cumulative lifetime cost of spectacles and contact lenses. In lower-resource settings, where access, replacement, durability, and continuity are more fragile, the logic may be even stronger.

The next step should be obvious. Refractive surgery should be included in serious health-economic modelling of global eye care. It should be compared properly with spectacles and contact lenses, not ignored because it developed largely in the private sector. We should be measuring not only procedure cost, but quality of life, years of disability avoided, effects on productivity, effects on education, and the broader economic gains that come when people can function naturally without ongoing dependence on external visual aids.

In that sense, refractive surgery belongs within the same broad moral framework as other forms of vision restoration.

None of this means surgery is the answer for everyone. It is not. Spectacles remain essential. Contact lenses remain important. Cataract surgery remains central. But global eye health should not artificially exclude one of the few interventions capable of providing permanent visual correction simply because it has historically sat outside the standard public health narrative.

For patients searching online for laser eye surgery, LASIK, SMILE, PRESBYOND, reading vision, ageing eyes, or for London Vision Clinic or EuroEyes Group clinics, this broader argument may seem distant from the personal question of whether surgery is right for them. In fact, it is closely related. The same qualities that make refractive surgery meaningful for an individual patient - accuracy, safety, stability, reversibility in some treatment strategies, independence from glasses, and restoration of natural visual function - are the very qualities that make it relevant on a global scale.

At London Vision Clinic, the same principle applies as it does in global eye health: permanent vision correction only has value when it is built on rigorous diagnostics, careful patient selection, surgical precision, and long-term commitment to visual quality.

That is why I believe the time has come to stop thinking of refractive surgery as merely cosmetic.

Laser eye surgery is not just about convenience. Refractive surgery is not just about lifestyle. In the right patient, and in the right setting, it is a durable way of restoring function. And in a world where uncorrected refractive error remains one of the commonest causes of visual impairment, it deserves to be recognised as part of the solution.

If global eye health is serious about reducing avoidable visual disability, then refractive surgery should no longer sit outside that conversation.

It belongs in it.

ABOUT THE AUTHOR

Professor Dan Reinstein is a world-leading refractive surgeon, founder of London Vision Clinic, inventor of PRESBYOND Laser Blended Vision, and an international authority on LASIK, SMILE and the surgical correction of presbyopia. He was the first to develop corneal epithelial mapping. His work has contributed to both the scientific development of modern refractive surgery and its application in global eye health initiatives.

REFERENCES

Reinstein DZ. The Time Has Come for Refractive Surgery to Be Included in the Fight Against Global Visual Impairment Due to Uncorrected Refractive Error. Journal of Refractive Surgery. 2022;38(1):6-8.

Burton MJ, Ramke J, Marques AP, et al. The Lancet Global Health Commission on Global Eye Health: vision beyond 2020. Lancet Global Health. 2021;9(4):e489-e551.

Reinstein DZ, Carp GI, Pradhan KR, et al. Role of laser refractive surgery in cross-subsidization of nonprofit humanitarian eyecare and the burden of uncorrected refractive error in Nepal: pilot project. Journal of Cataract and Refractive Surgery. 2018;44(8):1012-1017.

Pradhan KR, Reinstein DZ, Carp GI, Archer TJ, Gobbe M, Dhungana P. Quality control outcomes analysis of small-incision lenticule extraction for myopia by a novice surgeon at the first refractive surgery unit in Nepal during the first 2 years of operation. Journal of Cataract and Refractive Surgery. 2016;42(2):267-274.

Sandoval HP, Donnenfeld ED, Kohnen T, et al. Modern laser in situ keratomileusis outcomes. Journal of Cataract and Refractive Surgery. 2016;42(8):1224-1234.

Blum M, Lauer AS, Kunert KS, Sekundo W. 10-year results of small incision lenticule extraction. Journal of Refractive Surgery. 2019;35(10):618-623.

Reinstein DZ, Archer TJ, Gobbe M. LASIK for myopic astigmatism and presbyopia using non-linear aspheric micro-monovision with the Carl Zeiss Meditec MEL 80 platform. Journal of Refractive Surgery. 2011;27(1):23-37.

Reinstein DZ, Carp GI, Archer TJ, Gobbe M. LASIK for the correction of presbyopia in emmetropic patients using aspheric ablation profiles and a micro-monovision protocol with the Carl Zeiss Meditec MEL80 and VisuMax. Journal of Refractive Surgery. 2012;28:531-541.

Reinstein DZ, Couch DG, Archer TJ. LASIK for hyperopic astigmatism and presbyopia using micro-monovision with the Carl Zeiss Meditec MEL80 platform. Journal of Refractive Surgery. 2009;25(1):37-58.

This is not a story about fake data. It is a story about how real data can be used to create a false impression.

The He and Bala paper is bona fide (PubMed). It is a real peer-reviewed paper, and it reports the outcomes in the correct format using the standard graphs. It reports that at 3 months 100% of eyes were 20/20 or better, 89% were 20/16 or better, and 98% were within one line of preoperative corrected distance visual acuity. There is nothing wrong with that reporting. The problem starts when those numbers are lifted out of context and turned into marketing. (1-3)

To understand why the 20/16 rate was so high, you have to inspect the paper rather than just read the headline claim. This was a single-site private-practice series of consecutive myopic eyes, but it was also a very high-acuity cohort. The paper reports preoperative CDVA of -0.12 ± 0.06 logMAR in each eye, with a range from -0.20 to 0.00, and Figure 1A shows the cumulative postoperative UDVA curve against the preoperative CDVA curve. In practical terms, that means this was not a normal visual-potential distribution. The great majority of these eyes - roughly 90% from the graph - were already 20/16-capable before surgery with correction. So the study was not really asking, “In an ordinary first-come, first-served refractive population, how many eyes can this platform get to 20/16?” It was much closer to asking, “If you start with eyes that already have very high corrected acuity, how many still see that well once the prescription is removed?” (1)

That distinction matters. If one eye starts at 20/20 best-corrected and ends at 20/20 uncorrected at plano, that is an excellent result. If another starts at 20/16 best-corrected and ends at 20/16 uncorrected at plano, that is also an excellent result. In both cases the surgery has done the same essential job: it has removed the prescription while preserving the patient’s preoperative visual potential. The difference in the headline threshold is often the starting line, not the laser. That is exactly why the standard graphs were designed to compare postoperative UDVA with preoperative CDVA, rather than letting people treat a 20/16 rate as a stand-alone technology score. (2,3) (PubMed)

What Alcon has done in marketing WaveLight® Plus with InnovEyes™ is take the 20/16 number out of that context. Its U.S. website consumer page says “Go beyond 20/20” and states that over 98% achieved 20/20 or better and 89% achieved 20/16 or better. Its September 2025 launch release says that real-world data showed 100% of myopic patients restoring vision to 20/20 and 89% seeing 20/16. Its U.S. professional page foregrounds 100% at 20/20 and 89% at 20/16. Its international professional page foregrounds 98.1% at 20/20 and 82.5% at 20/16. None of those claims tells the reader the one thing needed to interpret them properly: that the underlying paper came from a high-acuity cohort in which most eyes were already capable of unusually good corrected vision. That is why the message is misleading to the public, and misleading to surgeons as well. (4-7) (MyAlcon)

The easiest way to see the issue is to change nothing except the denominator. In our own Journal of Refractive Surgery publication of SMILE in all-comers in 3,986 plano-target eyes, 55% were 20/16 with correction (compared to 90% in the He and Bala paper) before surgery and 63% of eyes achieved 20/16 or better without correction after surgery. Then I restricted the analysis to eyes that were already 20/16 or better before surgery with correction. The postoperative 20/16 rate immediately rose to 79%. Then I restricted the analysis again to eyes that were already 20/12.5 or better preoperatively. The postoperative 20/16 rate rose again, to 95%. Same surgery. Same dataset. Same analysis. Just a different denominator. In other words, you can create a spectacular postoperative 20/16 rate simply by excluding the eyes that were never 20/16-capable in the first place. (8-10)

SMILE - normal population [J Refract Surg. 2022;38(8):488-496]

SMILE - only 20/16 capable eyes same cohort

That is why my criticism is not that the He and Bala paper is dishonest. It is not. The paper is scientifically fairer than the advertising because it gives the reader the graph and the normalised comparison. My criticism is that Alcon is using a selected-cohort 20/16 rate as though it were a technology rate for an ordinary refractive population. It is presenting a number that came from a high-acuity cohort as though it were what a normal walk-through-the-door patient should expect. That is not a fair reading of the science. (1,4-7) (PubMed)

A fairer claim would have been simple: “In a very high-acuity cohort, 89% achieved 20/16 and 98% were within one line of their preoperative corrected acuity. That would still sound impressive. It would also be honest about what was actually studied. The science is bona fide. The spin is not. (1,4-7) (PubMed)

REFERENCES

1. He G, Bala C. Ray-tracing-guided myopic LASIK: real-world clinical outcomes. J Cataract Refract Surg. 2023;49(11):1140-1146. PubMed.

2. Reinstein DZ, Waring GO III. Graphic reporting of outcomes of refractive surgery. J Refract Surg. 2009;25(11):975-978. PubMed.

3. Reinstein DZ, Archer TJ, Randleman JB. JRS standard for reporting astigmatism outcomes of refractive surgery. J Refract Surg. 2014;30(10):654-659. PubMed.

4. Alcon. WaveLight Plus: Fully Custom LASIK Surgical Procedure - U.S. consumer page. https://www.myalcon.com/lasik/wavelight-plus/.

5. Alcon. Alcon Announces First Fully Personalized LASIK Treatment with WaveLight Plus in the U.S. and Canada. Media release, September 9, 2025. https://www.alcon.com/media-release/alcon-announces-first-fully-personalized-lasik-treatment-wavelight-plus-us-and-canada/.

6. Alcon. WaveLight Plus - U.S. professional page. https://www.myalcon.com/professional/refractive/wavelight-plus/.

7. Alcon. WaveLight Plus - international professional page. https://www.myalcon.com/international/professional/refractive/wavelight-plus/.

8. Reinstein DZ, Carp GI, Archer TJ, Vida RS, Yammouni R. Large Population Outcomes of Small Incision Lenticule Extraction in Young Myopic Patients. J Refract Surg. 2022 Aug;38(8):488-496. PubMed.

9. Reinstein DZ, Archer TJ. Audit of SMILE Primary Outcomes - Myopia: preoperative CDVA 20/16 only, London Vision Clinic, 2,036 eyes. Unpublished internal analysis.

10. Reinstein DZ, Archer TJ. Audit of SMILE Primary Outcomes - Myopia: preoperative CDVA 20/12.5 only, London Vision Clinic, 166 eyes. Unpublished internal analysis.

If you are considering ICL surgery and you have been Googling questions like “how is ICL size chosen?”, “is ICL reversible?”, “can an ICL be removed?”, “ICL vault too high”, or “ICL sizing ultrasound”, this article is for you. ICL stands for implantable collamer lens: in simple terms it is like a permanent contact lens placed inside the eye, between the iris (the coloured part) and your natural lens. For many people with high short-sightedness and astigmatism the results can be genuinely transformative. The optics are excellent, the vision can be crisp, and it avoids reshaping the cornea.

But there is one part of ICL surgery that matters far more than most patients realise, and it is not the prescription itself. It is the size of the lens.

WHY SIZE MATTERS

An ICL has to fit your eye. If it is too small, it can sit too close to your natural lens and the safety clearance can be too low. If it is too large, it can push structures forward, narrow the internal drainage angle, release pigment, and raise eye pressure. In some cases, the right solution is to remove or exchange the lens. These are not abstract risks. They are exactly the problems surgeons end up managing when sizing has not been right.

When you read about ICL safety, you will often see the word “vault”. Vault simply means the clearance between the ICL and your natural crystalline lens. Too little clearance is associated with higher cataract risk; too much clearance can be associated with angle narrowing, pigment dispersion and pressure problems. The point is not to memorise numbers. The point is to understand that “fit” is not a vague concept in ICL surgery. It is the central safety variable.

WHERE THE ICL ACTUALLY SITS

Here is the key idea in plain language. The place where the ICL sits is not on the outside of the eye. It sits behind the pupil, behind the iris - the coloured curtain behind the cornea. Measuring the front doesn’t tell you what’s happening behind the curtain.

That is why the method used to choose ICL size matters. Some clinics still rely heavily on external measurements taken from the front of the eye, especially the visible width of the cornea from “white-to-white”. This can work well in many eyes, but it is still an estimate. It uses what is easy to measure from the outside as a substitute for the internal anatomy that actually determines fit.

DIRECT MEASUREMENT VS ESTIMATED MEASUREMENT

A useful way to think about this is the “door” analogy. Measuring the doorway doesn’t tell you what’s behind the door, even if you think you can infer it from what you see on the outside. The rooms might be typical, or you might open the door and discover something unusual. In medicine we have a similar saying: if you hear hoofbeats, think horses, not zebras. Most of the time that is sensible. But zebras exist. Outliers exist. In ICL sizing, the outliers are not trivia. They are the patients whose lives can be made worse if assumptions replace direct measurement.

The challenge is that the iris is opaque. Light-based scanners can give exquisite detail about structures in front of the iris, but they cannot see through it under normal conditions. Ultrasound can, because ultrasound uses sound waves rather than light. It is exactly the same principle as obstetric ultrasound. A baby is inside the womb, inside the abdomen, inside the skin. You cannot see any of it with light. You can image it with sound. In ICL sizing, the anatomy that matters sits behind the iris. If you do not image behind the iris, you are estimating.

WHAT THIS MEANS FOR THE WAY YOUR CLINIC MEASURES YOU

There is, in practice, a ladder of sizing quality. External measurements such as white-to-white are quick and convenient, but they are proxies. Anterior segment OCT adds valuable information, but still mostly describes the front structures. Ultrasound that can characterise the anatomy behind the iris is the step that turns sizing from an estimate into a direct measurement problem.

This is not just opinion. Large studies have shown that white-to-white and the internal sulcus diameter do not correlate strongly, which is exactly why some eyes become “surprises” if you rely on external measurements alone. That is what patients experience as “they measured everything, so how could this happen?” The uncomfortable answer is that the most relevant structure may not have been measured directly.

IS ICL REVERSIBLE

Patients commonly ask whether ICL surgery is reversible. It is more accurate to say that the lens is removable or exchangeable. The ICL can be removed by a surgeon if clinically required, and this is routinely described by the manufacturer as an advantage compared with procedures that permanently reshape the cornea. The American Academy of Ophthalmology also publishes surgical teaching material on ICL removal, which reflects the clinical reality that explantation is a recognised procedure.

At the same time, it is still intraocular surgery. “Removable” does not mean “no consequences” or “risk-free”. It means that if your needs change, or if the sizing outcome is not ideal, there is a pathway to exchange or remove the lens rather than being locked into a corneal shape change forever. That distinction matters, and it is one reason many patients find ICL attractive. But it does not remove the obligation to size it properly the first time.

WHY SOME PEOPLE STILL NEED A SECOND OPERATION

Another common patient question is: “If the lens can be exchanged, is that just part of the process?” It should not be normalised as routine. An exchange is sometimes the right decision, but it is still a second operation inside the eye, and the entire purpose of good sizing is to reduce the likelihood of needing it.

This is also where incentives quietly matter. If the system makes it easy to order a lens based on quick external measurements, and if the consequences of a wrong size are largely borne by the patient and the surgeon later, then “good enough” can persist far longer than it should. That is not about conspiracy. It is about how workflows and friction shape what becomes standard.

WHAT MAXIMUM CARE LOOKS LIKE

In my own practice, we built our sizing pathway to reduce avoidable outliers by using multiple layers of checking. The principle is simple: if a lens sits behind an opaque curtain, you should measure behind the curtain. Then you should verify what you have done, and you should have a plan for the rare cases where the eye behaves unexpectedly.

This is why we use posterior chamber imaging, intraoperative measurement of vault and pupil size, and post-operative monitoring of vault and angle behaviour. The aim is not to make the process look complex. The aim is to make it safer and more predictable, particularly for the minority of eyes that do not behave like the average.

WHAT YOU SHOULD ASK AT YOUR CONSULTATION

If you want one practical takeaway, it is this. Ask your surgeon how they choose ICL size. Specifically ask whether they are estimating internal fit mainly from external measurements like white-to-white, or whether they directly image the anatomy behind the iris using ultrasound. Then ask how they monitor vault and angle after surgery, and what their threshold is for acting if vault is too high or too low.

That does not guarantee a perfect outcome. Nothing does. But it tells you whether the clinic is measuring what matters, or whether it is hoping that what is visible from the outside is an adequate substitute for what lies behind the curtain.

PATIENT FAQ

FAQ 1: How is ICL size chosen?
If you are searching “how is ICL size chosen” or “ICL sizing measurement”, the short answer is that the lens size should be chosen based on the internal anatomy where the ICL actually sits, not just on your prescription. The ICL sits behind the iris, so the safest approach is to measure the structures behind the iris that support the lens, rather than relying mainly on external proxy measurements from the front of the eye.

FAQ 2: What is white-to-white measurement for ICL sizing, and is it reliable?
If you are searching “white-to-white ICL sizing” or “is white-to-white accurate for ICL”, white-to-white is simply the visible width of the cornea measured from the outside. It can be a convenient starting point, but it is still an external estimate being used to predict an internal fit. It works in many eyes, but it is most vulnerable in the outlier eyes where the outside does not reliably predict the inside, which is precisely where you want the sizing to be most robust.

FAQ 3: Why do some surgeons recommend ultrasound for ICL sizing?
If you are searching “ultrasound ICL sizing” or “sulcus to sulcus ICL measurement”, the reason is straightforward: the key anatomy is behind the iris, and the iris is an opaque curtain. Light-based scans can give exquisite information in front of that curtain, but ultrasound can image behind it under natural conditions, which makes the sizing decision closer to direct measurement and less like inference.

FAQ 4: Is ICL reversible? Can an ICL be removed?
If you are searching “is ICL reversible” or “can an ICL be removed”, the most accurate phrasing is that ICL is removable or exchangeable if there is a clinical reason to do so. That is a real advantage compared with procedures that permanently reshape the cornea. But it is still intraocular surgery, so “reversible” should not be interpreted as casual or consequence-free; it simply means there is an established pathway to remove or exchange the lens if needed, and the goal is always to size it well enough that you never need to rely on that pathway.

FAQ 5: Does ICL give better night vision than LASIK or SMILE?
If you are searching “ICL vs LASIK night vision” or “ICL halos at night”, there is no universal truth that ICL automatically gives better night vision. Night symptoms depend on pupil size in the dark, centration, optical zone strategy, and the individual optics of your eye. In well-screened eyes with low-to-moderate myopia, modern laser surgery can have excellent night-vision outcomes when planned properly, and it is not accurate to suggest that ICL is categorically superior, especially as a blanket claim for myopia under about -7.00 D in most typical cases.

FAQ 6: “ICL doesn’t remove tissue” - is removing corneal tissue actually bad?
If you are searching “ICL no tissue removed” or “is removing corneal tissue dangerous”, it is true that ICL does not remove corneal tissue, but that does not make tissue removal inherently bad. Corneal laser vision correction works by reshaping the cornea, and decades of global experience have shown that, in suitable corneas and with proper screening, this can be a safe and effective mechanism. The meaningful question is not whether tissue is removed, but whether your cornea is suitable for laser safely, and whether your eye is suitable for an intraocular lens safely.

FAQ 7: Does ICL cause dry eye?
If you are searching “ICL dry eye” or “does ICL cause dry eyes”, ICL can still be associated with dryness or irritation, particularly in the early postoperative period, because surgery, drops, and surface inflammation can affect comfort even when corneal nerves are not the primary target. It is also not accurate to imply that laser procedures are uniquely “dry-eye causing” in modern practice; many patients experience only short-lived dryness after SMILE, and LASIK outcomes vary with baseline dry eye risk and how carefully the ocular surface is managed. The honest framing is that dryness is a spectrum and should be discussed in the context of your tear film, eyelid glands, screen use, and baseline symptoms, not as a slogan.

FAQ 8: What is ICL vault, and why do people worry about “vault too high” or “vault too low”?
If you are searching “ICL vault too high” or “ICL vault too low”, vault is the clearance between the ICL and your natural lens. Too low a vault means less clearance and can increase concern about cataract risk. Too high a vault can be associated with narrowing of the drainage angle and a higher chance of pressure or pigment-related issues. This is why vault is measured after surgery, why it is monitored over time, and why sizing accuracy matters so much upfront.

FAQ 9: Can wrong ICL sizing cause high eye pressure?
If you are searching “high eye pressure after ICL” or “ICL glaucoma risk”, an oversized lens can contribute to angle crowding, pigment dispersion, and pressure elevation in susceptible eyes, and these are precisely the complications that make surgeons take sizing seriously. Good preoperative measurement, thoughtful lens selection, and postoperative monitoring of the angle and pressure are the practical safeguards.

FAQ 10: Will I need an ICL exchange? What happens if the ICL size is wrong?
If you are searching “ICL exchange surgery” or “what if my ICL size is wrong”, an exchange is sometimes the correct solution, but it is still a second intraocular operation and should not be treated as trivial. The more useful question to ask your surgeon is what their sizing strategy does to reduce the chance of an avoidable exchange: do they mainly estimate from external measurements, do they directly image behind the iris with ultrasound, how do they check vault and angle, and what is their plan for recognising and managing the rare outlier eye early rather than late.

SIZING REFERENCES

• Reinstein MJB, Reinstein DZ, Archer TJ, Gupta R, Potter JG. Intraoperative OCT enables prediction of 3-month postoperative lens separation vault for the implantable collamer lens. J Refract Surg. 2025;41(6):e575-e584. doi:10.3928/1081597X-20250417-06.

• Assaf JF, Yazbeck H, Reinstein DZ, Archer TJ, Arbelaez J, Bteich Y, Arbelaez MC, Abou Mrad A, Awwad ST. Enhancing the automated detection of implantable collamer lens vault using generative adversarial networks and synthetic data on optical coherence tomography. J Refract Surg. 2024;40(4):e199-e207. doi:10.3928/1081597X-20240214-01.

• Assaf JF, Reinstein DZ, Zakka C, Arbelaez JG, Boufadel P, Choufani M, Archer T, Ibrahim P, Awwad ST. Deep learning-based estimation of implantable collamer lens vault using optical coherence tomography. Am J Ophthalmol. 2023;253:29-36. doi:10.1016/j.ajo.2023.04.008.

• Reinstein DZ, Archer TJ, Vida RS, Piparia V, Potter JG. New sizing parameters and model for predicting postoperative vault for the implantable collamer lens posterior chamber phakic intraocular lens. J Refract Surg. 2022;38(5):272-279. doi:10.3928/1081597X-20220302-01.

• Reinstein DZ, Vida RS, Archer TJ. Visual outcomes, footplate position and vault achieved with the Visian implantable collamer lens for myopic astigmatism. Clin Ophthalmol. 2021;15:4485-4497. doi:10.2147/OPTH.S330879.

• Reinstein DZ, Lovisolo CF, Archer TJ, Gobbe M. Comparison of postoperative vault height predictability using white-to-white or sulcus diameter-based sizing for the Visian implantable collamer lens. J Refract Surg. 2013;29(1):30-35. doi:10.3928/1081597X-20121210-02.

DISCLOSURE
I, Dan Reinstein am a consultant for Carl Zeiss Meditec (Jena, Germany) and CSO Italia (Florence, Italy), and have a proprietary interest in the Artemis Insight 100 technology (ArcScan Inc, Golden, Colorado) having developed it, including patents administered by the Cornell Center for Technology Enterprise and Commercialization (CCTEC), Ithaca, New York.

For more than two decades, implantable collamer lenses, usually called ICLs, have been presented as a mature, largely solved technology. The optics are excellent. The refractive accuracy is high. For high myopia, outcomes can be transformative. This article is about ICL sizing, why white-to-white persists, why vault and angle behaviour matter, and why ultrasound-based posterior chamber measurement should be the default. And yet one central problem has never been properly resolved, despite being well understood by anyone who has had to manage the consequences. That problem is sizing.

Sizing is not a marginal refinement. It is the dominant safety variable in posterior chamber phakic IOL surgery. The lens does not sit at the limbus and it does not sit in the anterior chamber. It sits behind the pupil, behind the iris, supported by the ciliary body. If it is undersized, the vault can be inadequate and the crystalline lens is placed at risk. If it is oversized, vault can be excessive, the angle can crowd, pigment can be released, pressure can rise, and sometimes the only rational move is urgent explantation. Most serious complication pathways in ICL surgery trace back to sizing, even when the proximate diagnosis is something else.

I have been interested in improving the safety of ICL surgery for about 20 years now. What is striking is not that sizing is hard, but that the default approach has remained essentially unchanged for decades. White-to-white corneal diameter, a surface measurement, is still widely used as a proxy for deep internal anatomy. The correlation is weak, and in outlier eyes it fails completely. This is not new knowledge. It is basic anatomy and basic statistics pretending to be a sizing strategy.

If we are honest about how sizing is done, there is a clear ladder of quality. White-to-white is a convenient external estimate. Anterior segment OCT adds meaningful information and reduces scatter, but it is still looking at structures in front of an opaque curtain. UBM begins to look behind the iris, but in most workflows it is lower frequency and operator-dependent, and it is not designed to deliver standardised, high-resolution ciliary body biometry at scale. Very-high-frequency digital ultrasound with robotic, user-independent acquisition directly images posterior chamber anatomy and currently represents the upper bound of what is achievable for sulcus/ciliary-body-informed sizing (for example, the Insight 100 system from ArcScan Inc, Colorado, USA). This isn’t a philosophical debate about technologies. It is simply the old rule: you cannot reliably predict what you refuse to measure.

Most conversations about sizing are framed around averages. Around models. They shouldn’t be. Safety fails in the tails. Improving mean predictability is valuable, but it does not answer the question that matters: which eyes are going to behave unexpectedly. Anterior-only models can tighten the distribution and still miss the very eyes that will drive the catastrophic cases, because those eyes are the ones where anterior anatomy does not predict posterior anatomy. No machine learning model built from anterior measurements can solve a posterior measurement problem. It can only become more confident in its own blind spot.

This is where the hoofbeats analogy becomes important. Most of the time, hoofbeats mean a horse, not a zebra. But the zebra cases are real. In ICL sizing, those outliers are not statistical trivia or intellectual curiosities. They are the patients whose lives can be made worse when assumptions replace direct measurement.

The iris is an opaque curtain. Light-based systems can generate exquisite images of the structures in front of that curtain, but they cannot see through it in physiological conditions. Ultrasound can, because ultrasound does not require optical transparency. It is exactly the same principle as obstetric ultrasound. A baby is inside the womb, inside the abdomen, inside the skin. You can’t see it with light. You can image it with sound. In ICL sizing, the anatomy that matters sits behind the iris. If you do not image behind the iris, you are estimating.

When posterior anatomy is directly measured, predictability improves dramatically. This has been shown repeatedly by experienced operators using handheld ultrasound, and when the same principles are implemented with standardised, robotic or user-independent acquisition, the improvement is not subtle. It is a step change. The cases that used to be explained away as “surprising” stop being surprising. They become visible and therefore preventable. In the country with the highest volume of ICL implantation, it is rapidly becoming standard to use ultrasound.

Against that background, it is reasonable to ask why this approach has not yet became the standard. At one point, the dominant manufacturer in this space carried a market capitalisation of around two billion dollars. Yet in all that time there was no serious, sustained investment in solving the sizing bottleneck at its root, and no meaningful shift away from an external proxy being treated as a primary sizing input. Even today, the historical default remains embedded in the way the field functions.

Instead, responsibility has been pushed downstream. Surgeons are told to learn their exchange rates, to manage complications as part of practice, and to accept that there will always be some percentage of patients who need a second operation. Replacement lenses may be provided, which is commercially convenient, but it does not make the patient whole. A free lens does not undo pigment dispersion, glaucoma surgery, or the permanent psychological harm of feeling something has gone wrong inside one’s eye. When the solution to a sizing failure is “we’ll swap it later,” it is worth asking why the sizing standard was not upgraded earlier.

The explanation often offered is that sizing innovation should be driven downstream by surgeons rather than upstream by the manufacturer. On the surface, that sounds collaborative. In reality, it is structurally ineffective. Surgeons do not control ordering systems. Surgeons do not control global defaults. Surgeons cannot rewrite the industry’s baseline workflow. If the upstream ecosystem remains anchored to an external estimate, downstream practice will follow, because friction shapes behaviour.

That brings us to incentives. In practice, surgeons and centres optimise for speed, convenience, and minimising disruption. If a safer pathway adds equipment, time, training, and workflow complexity, adoption will be slow unless the system makes it unavoidable. This is not malice. It is predictable human behaviour under operational pressure. That is exactly why it is disingenuous to claim that the responsibility should be left with individual surgeons while the upstream system quietly preserves the old defaults.

I often describe this as bronze, silver, and gold. White-to-white is bronze. It usually works and it is easy. Anterior OCT plus better modelling is silver. It reduces variability and improves average predictability. Direct posterior anatomy measurement is gold because it gives you the best chance of identifying the eyes that will otherwise bite you. The uncomfortable truth is that many people stop at bronze or silver because they can, not because it is best. Bronze can feel “good enough” until the day it isn’t.

The thing is, high-volume environments expose this brutally. But in low-volume practices, outliers feel anecdotal. In high-volume systems, they become a steady stream. A one percent issue is an abstraction until you are implanting hundreds or thousands of lenses a year. At that scale, the difference between estimating and measuring becomes operationally obvious. It also becomes ethically obvious.

There is a deeper economic reality as well. If a centre is faced with a choice between investing in safer sizing infrastructure or tolerating a higher exchange rate, many will choose the latter because the costs are externalised. The patient bears the risk. The surgeon bears the complication. The manufacturer keeps the workflow simple. Market forces reward convenience more than prevention unless leadership chooses otherwise.

It is also worth stating, without hyperbole, that I am not aware of any centre anywhere that applies more layers of scrutiny, redundancy, and error analysis to ICL sizing than the protocol I and co-workers Tim Archer, Joseph Potter and Ryan Vida have developed over the last 10 years at the London Vision Clinic. Pre-operatively, we directly image posterior chamber anatomy using very-high-frequency digital ultrasound with the Insight 100 from ArcScan Inc, combined with a non-linear multivariate regression model that we developed not only to predict vault, but also to predict angle configuration and how a given ICL choice will mechanically reshape the anterior segment. Intra-operatively, we add a second decision gate, because the eye on the table is not identical to the eye you measured in the clinic. Using intraoperative OCT integrated into the ARTEVO 800 from Carl Zeiss Meditec, we measure real-time vault and pupil size and combine those data with our pre-operative ciliary body metrics to predict, via a second multivariate model, how vault will evolve over the following months as the eye stabilises. This allows us to identify, on the operating table, those rare lenses that are statistically likely to settle too high or too low, and to exchange them immediately for a pre-selected alternative size identified through explicit error-propagation and probability modelling. In other words, our sizing process does not stop at choosing a lens. It formally anticipates its own failure modes. Post-operatively, vault and angle behaviour are monitored using high-resolution anterior segment OCT with the MS-39 from CSO Italia, and at three months we repeat VHF digital ultrasound imaging, which remains the only method capable of generating a true three-dimensional map of ICL-crystalline lens separation behind the iris under physiological conditions. Taken together, this represents the current upper bound of what is technically achievable in ICL sizing for an individual eye. It is also instructive, because it demonstrates that the question is not whether safer sizing is possible, but whether there is sufficient willingness to make it standard.

None of this is an argument against ICLs. On the contrary, if sizing were properly solved, they would become safer, more predictable, and more defensible than ever. The irony is that addressing the problem would strengthen the field rather than threaten it. What is troubling is not that the solution is hard, but that it was never treated as a primary obligation when it was clearly achievable.

Superior technology also does not automatically win. Even when better tools exist, adoption can fail if training, usability, and workflow integration are neglected. Innovation requires stewardship, not just invention. That lesson applies universally, including to those of us who have spent years trying to push the field forward.

I do not claim to know the motivations behind the decisions that shaped ICL sizing over the past two decades. Cost, inertia, fear of disruption, and complacency all play their part in any large system. But when a medical device ecosystem tolerates a known safety bottleneck for this long, it deserves scrutiny.

This is not about blame. It is about accountability. Medical progress is defined not only by what we invent, but by what we choose to make standard. When safer pathways exist and are sidelined, silence becomes a decision.

The question is not whether ICLs work. They do. The question is whether the way we have chosen to size them reflects scientific leadership, or institutional convenience.

That question is long overdue.

SURGEON FAQ
Question: Why can anterior-only modelling miss catastrophic outliers?
Answer: Because the failure mode is posterior support anatomy variance that is not captured by anterior measurements. The tails are enriched for eyes where anterior geometry does not predict posterior chamber/ciliary body dimensions.

Question: What is the practical role of intraoperative OCT in an ICL sizing workflow?
Answer: It can function as a second gate by measuring on-table vault and pupil size, enabling a modelled prediction of vault evolution and an immediate exchange decision when an outlier lands in a high-risk zone.

Question: What does “standardised, user-independent acquisition” change in practice?
Answer: It reduces operator variance, improves repeatability, and makes posterior anatomy-derived biometry scalable, which is the precondition for normalising direct measurement rather than treating it as a niche or artisan workflow.

Question: Why does pharmacologic dilation not solve the “behind the iris” problem for OCT?
Answer: Because dilation changes iris behaviour and ICL position, so the geometry is no longer physiological. You may reveal structures, but you distort the very relationships you are trying to measure.

REFERENCES

• Reinstein MJB, Reinstein DZ, Archer TJ, Gupta R, Potter JG. Intraoperative OCT enables prediction of 3-month postoperative lens separation vault for the implantable collamer lens. J Refract Surg. 2025;41(6):e575-e584. doi:10.3928/1081597X-20250417-06.

• Assaf JF, Yazbeck H, Reinstein DZ, Archer TJ, Arbelaez J, Bteich Y, Arbelaez MC, Abou Mrad A, Awwad ST. Enhancing the automated detection of implantable collamer lens vault using generative adversarial networks and synthetic data on optical coherence tomography. J Refract Surg. 2024;40(4):e199-e207. doi:10.3928/1081597X-20240214-01.

• Assaf JF, Reinstein DZ, Zakka C, Arbelaez JG, Boufadel P, Choufani M, Archer T, Ibrahim P, Awwad ST. Deep learning-based estimation of implantable collamer lens vault using optical coherence tomography. Am J Ophthalmol. 2023;253:29-36. doi:10.1016/j.ajo.2023.04.008.

• Reinstein DZ, Archer TJ, Vida RS, Piparia V, Potter JG. New sizing parameters and model for predicting postoperative vault for the implantable collamer lens posterior chamber phakic intraocular lens. J Refract Surg. 2022;38(5):272-279. doi:10.3928/1081597X-20220302-01.

• Reinstein DZ, Vida RS, Archer TJ. Visual outcomes, footplate position and vault achieved with the Visian implantable collamer lens for myopic astigmatism. Clin Ophthalmol. 2021;15:4485-4497. doi:10.2147/OPTH.S330879.

• Reinstein DZ, Lovisolo CF, Archer TJ, Gobbe M. Comparison of postoperative vault height predictability using white-to-white or sulcus diameter-based sizing for the Visian implantable collamer lens. J Refract Surg. 2013;29(1):30-35. doi:10.3928/1081597X-20121210-02.

DISCLOSURE
I, Dan Reinstein am a consultant for Carl Zeiss Meditec (Jena, Germany) and CSO Italia (Florence, Italy), and have a proprietary interest in the Artemis Insight 100 technology (ArcScan Inc, Golden, Colorado) including patents administered by the Cornell Center for Technology Enterprise and Commercialization (CCTEC), Ithaca, New York.

INTRODUCTION: WHY THIS ARTICLE EXISTS

I often meet surgeons who are entirely comfortable with myopic corneal surgery yet feel cautious, or even uneasy, about treating hyperopia on the cornea. That caution is understandable, because hyperopic outcomes historically varied more widely between surgeons, platforms and eras than myopic outcomes. The problem is that the conclusions drawn from those older experiences were frequently broader than the underlying causes. Corneal hyperopic surgery is, in fact, very safe and very effective when it is done with the appropriate optical reference points, biologically informed constraints, and a refraction protocol designed for hyperopes rather than borrowed from myopia. Hyperopia is not “myopia with the sign flipped”. It is a different geometry and a different healing environment, with different variables that matter most.

Before I get into why corneal hyperopia is so often misunderstood, it is worth stating where this perspective comes from. Much of what I will describe here was built over decades of research and clinical work using very high frequency digital ultrasound epithelial and stromal scanning with the Artemis platform, including the Artemis Insight 100. I was one of the inventors of that technology along with Ronald H Silverman, PhD and D Jackson Coleman, MD, and we retain a financial interest in it. It has been a central tool in my work since the 1990s to characterise epithelial remodelling, optical zone behaviour, and the biological constraints that make hyperopic corneal surgery both predictable and safe when done properly. The insights that follow are therefore not theoretical; they are the consequence of repeatedly measuring what actually happens in the cornea, at high resolution, in large numbers of real eyes, over long follow-up, and then iterating surgical planning and technique accordingly. References at the bottom of this article.

In this piece I want to bridge that knowledge gap in a way that is directly usable in clinic. I will cover the core concepts that explain why hyperopic treatments were historically perceived as unpredictable, why that perception persists, and what practical rules make modern hyperopic LASIK and hyperopic SMILE Pro far more consistent than many surgeons expect. I will also introduce two feasibility ideas that I have found useful for hyperopic SMILE adoption: VTLDmin, meaning a vertex-to-limbus distance minimum concept, and the pragmatic “white-to-white minus angle kappa” screen as a rough guide to whether hyperopic SMILE geometry is likely to be workable in a given eye.

HYPEROPIA AS A DIFFERENT BIOLOGICAL PROBLEM: WHY “REGRESSION” WAS DISCUSSED SO MUCH

A central historical theme in hyperopic corneal surgery is the idea of regression. In the early years of hyperopic profiles, surgeons saw cases where the refractive effect reduced substantially over time and naturally looked for explanations such as latent hyperopia, accommodative artefacts, or measurement issues. With modern epithelial mapping and a better understanding of corneal remodelling, a large part of that narrative becomes more concrete. Hyperopic corneal treatments create a steep rate of change of curvature toward the centre. The epithelium responds to that stimulus. It can thicken in predictable zones, particularly around the edge of the optical zone, and the degree and pattern of remodelling vary between individuals.

This variability matters because it can make keratometry behave in ways that feel counterintuitive. You may see greater scatter in postoperative Ks than in postoperative refraction, and that is one reason some hyperopic work has historically felt less “tight” than myopia. That does not mean the refractive outcome is random. It means that epithelial remodelling contributes to the achieved anterior curvature in a patient-specific way. Once you expect that, you stop being surprised by it and start planning around it.

EPITHELIAL VIABILITY AS A PRIMARY CONSTRAINT: WHY K VALUES CAN MISLEAD IN HYPEROPIA

Many surgeons were trained to use keratometry as a primary proxy for “how far you can safely go” in corneal surgery. In hyperopia, that habit can be less helpful than it is in myopia, particularly when planning enhancements. The more clinically useful constraint is epithelial viability at the thinnest point. In practice, epithelial breakdown begins around the mid-20 micron range, and a conservative operative floor is to avoid driving the thinnest epithelial point below 30 microns.

The important nuance is that epithelial reserve is not reliably predicted by the absolute K reading. You can see an eye with relatively modest Ks that nonetheless has limited epithelial reserve and therefore limited safe “headroom” for further hyperopic steepening. You can also see a very steep cornea with epithelial reserve that makes an enhancement entirely reasonable. When surgeons rely on Ks alone, they can end up making opposite errors: treating when they should be cautious, or withholding when the biology would permit further correction. One practical consequence is that epithelial mapping becomes far more than a diagnostic curiosity in hyperopia; it becomes a safety tool for enhancement decision-making.

REFERENCE POINTS AND CENTRATION: WHY HYPEROPIA EXPOSES THE LIMITS OF PUPIL-CENTRED HABITS

Centration sensitivity is not unique to hyperopia, but hyperopia is far less forgiving of centration drift. The clinically useful principle is that the corneal vertex is the stable reference for corneal shape and corneal aberration analysis, and it is the anchor around which corneal treatments behave most predictably in eyes with non-zero angle kappa. This is also where confusion historically arose, because whole-eye wavefront measurements are often presented in pupil-centred coordinates, which can make eyes with angle kappa appear to have coma that is largely a coordinate artefact.

The practical point is not to argue about which concept is “right” in the abstract. The practical point is that a centration strategy needs to be internally consistent with the reference frame in which you evaluate optics, topography and patient symptoms. When those reference frames are mixed, surgeons can be led toward choices that appear reasonable within one measurement system while producing avoidable optical consequences on topography and patient experience. Over time, those mixed-reference outcomes contributed to the belief that hyperopic corneal treatments are intrinsically unreliable. In my view, much of that reputation reflects reference-frame inconsistency rather than a fundamental limitation of hyperopic corneal surgery.

HYPEROPIC SMILE PRO IN CONTEXT: WHY EARLY LENTICULE DESIGNS UNDERPERFORMED, AND WHAT A “HYPEROPIA-APPROPRIATE” DESIGN CHANGES

Hyperopic lenticule extraction had an early phase in which outcomes were less reassuring than many of us would accept today. With hindsight, the reasons are unsurprising. Hyperopic geometry is transition-zone dependent. If optical zones are small, transition zones are short, and centration is treated as a pupil-centred default, the combination can create an unfriendly curvature gradient and a less predictable epithelial response. A more hyperopia-appropriate design incorporates a meaningful transition zone, with an optical zone that respects the biology of curvature change rather than simply aiming for maximal steepening.

One interesting observation in early series using improved hyperopic lenticule geometry is that the apparent topographic optical zone can be larger after hyperopic SMILE than after hyperopic LASIK for a similar nominal programmed diameter. A plausible explanation is that excimer tissue removal fidelity reduces toward the periphery, and transition-zone fidelity becomes the limiting factor in how the cornea ultimately remodels. With SMILE, the cut geometry is what was programmed across the diameter, which may reduce the stimulus for epithelial “filling-in” that contracts the apparent topographic optical zone. Whether that proves to be the entire mechanism is less important than the clinical implication: the delivered geometry in the periphery may be closer to the intended geometry.

PARAMETERS THAT MATTER IN HYPEROPIA: CAP THICKNESS, MINIMUM LENTICULE THICKNESS, AND WHY THE TRADE-OFFS DIFFER FROM MYOPIA

Some parameters that feel routine in myopia require a different balance in hyperopia. Cap thickness is a good example. In myopic SMILE, very thin caps can complicate future enhancement strategies if LASIK-on-SMILE is needed. Hyperopia differs because hyperopic eyes are more likely to need enhancement and because the central tissue removal profile differs. A 120 micron cap can be a sensible choice in hyperopic SMILE because it can preserve a more favourable enhancement landscape and avoid creating an excessively thin region where there is little central tissue removal to “buffer” a thin cap choice.

Minimum lenticule thickness is another parameter that deserves attention rather than assumption. In low myopia, increasing minimum lenticule thickness can improve early visual recovery. In hyperopia, the same concept may prove useful, but the relationship needs to be learned in a disciplined way rather than extrapolated from myopia. This is precisely the kind of optimisation question that benefits from a coordinated early adopter group and consistent postoperative documentation.

POSTOPERATIVE HEALING PATTERNS: INTERFACE HAZE AS A PRACTICAL CONSIDERATION AND A PROPOSED MANAGEMENT POSTURE

In early hyperopic SMILE experience, one clinically important signal has been interface haze that can peak later than we are used to seeing in routine myopic SMILE and can persist in a smaller subset at longer follow-up. This pattern suggests a tissue-response phenotype rather than simply a short-term clarity fluctuation. A biologically plausible explanation is that mid-peripheral stromal tissue behaves differently from central stromal tissue with respect to keratocyte activation and stromal remodelling, and that hyperopic geometry concentrates the relevant stimulus in a different stromal geography than myopia.

A practical, cautious posture in early hyperopic SMILE adoption is therefore to modulate healing more like a PRK-style risk profile than a myopic SMILE profile, at least until consistent local outcomes and broader datasets confirm the optimal approach. After the initial first postoperative week of combined coverage according to your standard regimen, a steroid tail using fluorometholone for around a month, with appropriate intraocular pressure checks and individualisation for responders, is a rational strategy aimed at reducing the incidence and persistence of interface haze. It is simple, testable, and can be refined as data accumulate.

For monitoring, infrared-based interface evaluation can be very helpful. Devices such as the MS-39 can reveal interface scatter changes in a way that is sometimes more sensitive than white-light slit-lamp impressions. Earlier visibility supports earlier intervention and can prevent a transient interface phenotype from becoming a prolonged patient experience.

FEASIBILITY AND DOCKING GEOMETRY IN HYPEROPIC SMILE: VTLDmin AND WHITE-TO-WHITE MINUS ANGLE KAPPA

Hyperopic SMILE feasibility is not only a question of whether a nominal white-to-white meets a published cutoff. Hyperopes commonly have larger angle kappas. When you centre a treatment appropriately relative to the vertex-related axis rather than the pupil centre, the treatment is shifted toward the limbus on one side. In a borderline-sized cornea, that shift can reduce the remaining margin between the edge of the cap or lenticule zone and the limbus to a point where docking and cutting become less forgiving, particularly if there is subtle peripheral pannus or contact lens–related change.

This is where it is helpful to think in terms of VTLDmin, a vertex-to-limbus distance minimum concept. The relevant question becomes: once the treatment is shifted by the patient’s angle kappa, what is the minimum remaining distance from the intended optical centre to the limbus on the shifted side? That is the practical reserve you are relying on.

As a rough, conservative screen, I have suggested thinking of “white-to-white minus angle kappa” as a proxy for this reserve. It is not a precise anatomical equation, but it captures the idea that a large angle kappa effectively reduces usable limbal margin on the side toward which the optical centre is shifted. If your comfort threshold is 11.5 mm in a dataset, an eye that is 11.7 mm with a large angle kappa may behave as if it is below threshold in terms of peripheral safety margin. In early adoption, conservative screening is valuable because it reduces the number of cases where peripheral geometry rather than optical design becomes the dominant risk variable.

This is also where the practical difference between hyperopic LASIK and hyperopic SMILE becomes important. LASIK offers more freedom to manage geometry and access even in borderline diameters. SMILE is constrained by contact glass docking and by the interaction of a spherical interface with an aspheric, potentially tilted cornea. An eye can therefore be an excellent hyperopic LASIK candidate and still be a poor early hyperopic SMILE candidate. Recognising that distinction is part of keeping outcomes consistently excellent.

INTRAOPERATIVE CENTRATION BEHAVIOUR: THE SUCTION-APPLICATION SHIFT AND THE ROLE OF A LOW-DRAMA CONVERSION PLAN

A feature that deserves explicit attention in hyperopic SMILE is that suction application can produce a small but clinically meaningful shift, even when pre-suction alignment looks ideal. In myopia this often has minimal consequence. In hyperopia it can matter more. The practical implication is that a surgeon should have a clear, calm conversion plan and should feel entirely comfortable choosing not to proceed when centration after suction does not meet the standard you set.

This is why I prefer consenting patients for both SMILE and LASIK rather than for SMILE alone. A straightforward conversion option reduces the tendency to “push through” in a borderline docking situation. The goal is not to be dramatic; the goal is to keep early outcomes representative of the true capability of hyperopic SMILE, rather than blending learning-curve centration events into the narrative of the procedure itself.

REFRACTION IN HYPEROPIA: WHY PROCESS MATTERS MORE THAN A SINGLE NUMBER

Hyperopic outcomes depend heavily on refraction technique. Older heuristics about averaging cycloplegic and manifest values are not a reliable foundation for modern hyperopic planning. A discrepancy between cycloplegic and manifest should be treated as a prompt to repeat the manifest carefully, with time, rather than as a prompt to split the difference.

In hyperopes, giving time for the refraction to “settle” can be the difference between a stable plan and an iatrogenic myopic surprise. A practical approach is to place plus in front of the patient and allow enough time for accommodation and adaptation to relax. Cycloplegic refraction can be influenced by lens position effects, and in some eyes the cycloplegic value may not be the best guide to what the patient functions with in the real world. The operational principle is that treatment should be based on a robust manifest refraction obtained with a hyperopia-appropriate protocol and confirmed for repeatability, ideally across separate visits.

CONCLUSION: WHY THE CORNEA WAS NEVER THE PROBLEM

Corneal hyperopic surgery is safe when it is approached as its own category, with the right biological constraints, the right optical reference points, and a refraction process designed for hyperopes. Much of the historical scepticism around hyperopia reflects a legacy of variable transition-zone design, inconsistent reference frames for centration and optical analysis, and enhancement decisions driven by keratometry alone rather than epithelial viability. Hyperopic SMILE Pro adds a powerful new option, but it also introduces feasibility and docking geometry considerations that are less prominent in LASIK. Concepts such as VTLDmin and the pragmatic “white-to-white minus angle kappa” screen are ways to keep early adoption conservative and outcomes consistently strong, while postoperative modulation strategies such as a fluorometholone tail can address interface haze risk that appears more relevant in hyperopic lenticule work than in routine myopic SMILE.

If we treat hyperopia as “different from myopia” rather than as “myopia with a plus sign”, then the procedure stops being a folklore problem and becomes what it should be: a disciplined, biologically informed refractive correction with predictable safety and outcomes.

REFERENCES

Reinstein DZ, Silverman RH, Sutton HF, Coleman DJ. Very high-frequency ultrasound corneal analysis identifies anatomic correlates of optical complications of lamellar refractive surgery: anatomic diagnosis in lamellar surgery. Ophthalmology. 1999 Mar;106(3):474-482. doi:10.1016/S0161-6420(99)90105-7. PMID:10080202.

Reinstein DZ, Couch DG, Archer TJ. LASIK for hyperopic astigmatism and presbyopia using micro-monovision with the Carl Zeiss Meditec MEL80 platform. J Refract Surg. 2009 Jan;25(1):37-58. doi:10.3928/1081597X-20090101-07. PMID:19244952.

Reinstein DZ, Archer TJ, Gobbe M, Silverman RH, Coleman DJ. Epithelial thickness after hyperopic LASIK: three-dimensional display with Artemis very high-frequency digital ultrasound. J Refract Surg. 2010 Aug;26(8):555-564. doi:10.3928/1081597X-20091105-02. PMID:19928697.

Reinstein DZ, Gobbe M, Archer TJ. Coaxially sighted corneal light reflex versus entrance pupil center centration of moderate to high hyperopic corneal ablations in eyes with small and large angle kappa. J Refract Surg. 2013 Aug;29(8):518-525. doi:10.3928/1081597X-20130719-08. PMID:23909778.

Reinstein DZ, Gobbe M, Archer TJ, Carp GI. Mechanism for a rare, idiosyncratic complication following hyperopic LASIK: diurnal shift in refractive error due to epithelial thickness profile changes. J Refract Surg. 2016 Jun;32(6):364-371. doi:10.3928/1081597X-20160428-05. PMID:27304599.

Reinstein DZ, Carp GI, Archer TJ, Buick T, Gobbe M, Rowe EL, Jukic M, Brandon E, Moore J, Moore T. LASIK for the correction of high hyperopic astigmatism with epithelial thickness monitoring. J Refract Surg. 2017 May;33(5):314-321. doi:10.3928/1081597X-20170111-04. PMID:28486722.

Reinstein DZ, Carp GI, Archer TJ, Day AC, Vida RS. Outcomes for hyperopic LASIK with the MEL 90 excimer laser. J Refract Surg. 2018 Dec;34(12):799-808. doi:10.3928/1081597X-20181019-01. PMID:30540362.

Reinstein DZ, Morral M, Gobbe M, Archer TJ. Accuracy of refractive outcomes in myopic and hyperopic laser in situ keratomileusis: manifest versus aberrometric refraction. J Cataract Refract Surg. 2012 Nov;38(11):1989-1995. doi:10.1016/j.jcrs.2012.05.045. PMID:23079314.

Gobbe M, Reinstein DZ, Archer TJ. LASIK-induced aberrations: comparing corneal and whole-eye measurements. Optom Vis Sci. 2015 Apr;92(4):447-455. doi:10.1097/OPX.0000000000000557. PMID:25785529.

If you’re thinking about laser eye surgery and your immediate reaction is, I could never do that, you’re in very familiar territory. People hear “it doesn’t hurt” and they nod, but internally they still picture pain, panic, and the fear of doing something wrong at exactly the wrong moment. Then they come back the next day and say, with genuine surprise, that it was nothing.

A patient said to me today, “I must admit that at the whole start of this point in time, the worst thing for me was the anticipation of yesterday morning.” That is the part almost nobody expects. The fear beforehand often feels more intense than the experience itself, because before you’ve done it your brain can only simulate it, and those simulations are almost always pessimistic.

He described that build-up very plainly: “I built myself up psychologically. There was either going to hurt or… No. Nothing. Zero. Nothing.” And when someone asked him to put a number on it, he repeated what he’d been told beforehand and then recognised it was true: “Did discomfort out of ten? … I might have had zero point five - half - out of ten.” Half out of ten. Not pain in the way people imagine it, but the kind of minimal odd sensation you’d rate as barely there.

What’s interesting is that this surprise isn’t limited to nervous patients who don’t know what to expect. I’ve seen it in people who know the field, understand the technology, and are completely comfortable making the decision. My business partner, Craig Engelfried, is one of those people. Craig and I have known each other since we were 12, we met at school in London, we’re both American, and we founded London Vision Clinic together in 2002, 30 years later. When he became presbyopic, he chose to have PRESBYOND at a

ge 48, when he started to struggle with near vision, holding things a little further back - before he had even bought a pair of reading glasses. He wasn’t hesitant about surgery at all. And yet afterwards he was still taken aback by how easy it felt, to the point that his quote has stuck with me ever since: “It was less uncomfortable than brushing your teeth!”

That’s the psychological mismatch that keeps repeating in clinic. It’s not that people weren’t reassured. It’s that reassurance lives in words, and fear lives in the body. Eyes are precious, and anything involving them feels high-stakes. When something is high-stakes, the brain doesn’t readily accept “you’ll be fine” as a settled fact; it keeps a protective prediction running until it gets proof.

That’s why personal experience is so powerful. Before surgery, everything is second-hand, no matter how well it’s explained. After surgery, you have your own data point. The day after, many people aren’t just relieved that it went well; they’re surprised that the thing they thought they “could never do” turned out to be so undramatic.

None of this is to pretend everyone feels exactly the same, or that you should ignore your nerves. It’s simply to say that feeling anxious beforehand is not evidence that it will be painful. It’s the mind’s default response to an unknown that matters to you. For a great many patients, the shock afterwards is how wrong the prediction was.

Inge was one of those people. She had been short-sighted since infancy. Her early prescription was already high, and then it marched steadily upwards year after year. By the time she was 18, she was around -20. Over the following decades it continued to worsen, and by 2010, when she was 47, her prescription had reached -33, with around -5 of astigmatism on top. That combination is not just “strong glasses”. It is a different way of living in the world.

If you have never worn very high minus lenses, it can be hard to grasp what they do to daily life. The glasses are heavy. The lenses are thick. Peripheral vision is distorted. Your eyes look smaller behind the lenses. Your choice of frames is limited. And for a teenager, that can be quietly brutal. Inge described becoming self-conscious early, trying different frame styles, and still feeling trapped by what the optics demanded. Like many people in that situation, she moved into contact lenses as soon as she was allowed.

But contact lenses are not a single thing. The contact lenses available when she started were rigid, uncomfortable, and physiologically unforgiving. They reduced oxygen to the cornea and tended to inflame eyes that were already being asked to do too much. Dust, wind, and grit were not minor annoyances; they could be day-ruining events. Even as lens technology improved, her prescription meant she still needed hard lenses, and the daily routine remained relentless. People often underestimate the cognitive load of that life: the cleaning solutions, the case, the constant planning for overnight stays, the inability to fall asleep for ten minutes without first going through a careful removal process, the anxiety about water, sand, smoke, air-conditioning, a gust of wind at the wrong moment.

And then, as happens to all of us eventually, the near vision began to change too. Inge noticed the early signs of presbyopia in her early forties. It is one thing to struggle for distance, and another to find that reading is slipping away as well.

By the time she came to see me, she had largely made her peace with the idea that this was simply her lot. That resignation is common in people with very high prescriptions, because they have often been told—sometimes many times—that they are “too high” for laser, “too risky” for lens surgery, or “too thin” in the cornea to do anything meaningful. There is usually some truth behind each of those statements. The mistake is assuming they automatically add up to “nothing is possible”.

HOW I THINK ABOUT “IMPOSSIBLE” CASES

In refractive surgery, the word “unsuitable” is not a single diagnosis. It is a conclusion reached from a set of constraints. If you change the constraints—by changing the technique, or the sequence, or the technology, or the goals—you sometimes change the conclusion.

In Inge’s case there were three big issues that had to be addressed honestly.

First, the prescription was extraordinarily high. Correcting -33 entirely with corneal laser alone is simply not realistic or safe. The amount of tissue that would need to be removed would exceed what the cornea can tolerate, and even if you could remove it, you would push optical quality into a zone where side effects would dominate.

Second, her corneas were thin. Thin corneas do not automatically mean “no laser”, but they do mean that any laser component has to be planned with extreme discipline, using accurate measurements, conservative assumptions, and a clear-eyed view of biomechanics.

Third, the lens-based alternative she had been offered elsewhere—clear lens exchange, sometimes casually called “lens replacement”—was not a good fit for her risk profile. In very high myopes, removing the natural lens can increase the risk of retinal detachment. That risk is not theoretical. It is a real, known association, and it has to be taken seriously. For someone who has already spent a lifetime managing vision challenges, exchanging one problem for a potentially blinding complication is not the trade anyone wants to make lightly.

So, if corneal laser alone was not appropriate, and clear lens exchange carried an unacceptable retinal risk, where does that leave you?

It leaves you with the option that, in my view, is often underappreciated by patients until someone explains it carefully: the implantable collamer lens, or ICL. An ICL is, essentially, an internal contact lens placed inside the eye, behind the iris and in front of the natural lens. It can correct high prescriptions without removing corneal tissue and without removing the natural lens. In other words, it sits in the space between “laser only” and “lens exchange”, and for many high myopes it is the most elegant first step.

But even here, Inge’s numbers were at the extreme edge. The highest-power ICLs have limits. If you start at -33, even the maximum lens power may not get you all the way to zero. And if you are left with a significant residual prescription after ICL implantation, you still have to decide whether it can be safely treated on the cornea, given the corneal thickness.

This is where the work begins. Not the surgery. The thinking.

THE ROLE OF MEASUREMENT: WHY WE TESTED SO MUCH

When someone comes in with an extreme prescription, the “many tests and scans” are not theatre. They are the substance. You cannot plan a safe solution if you are guessing.

Inge underwent extensive diagnostic work, including high-precision mapping of her corneas. I remember that it was early in our experience with very high-frequency ultrasound scanning for the cornea. That technology matters because it allows us to measure corneal layers with a level of detail that conventional methods do not. It tells you not only the overall thickness, but the distribution, and the architecture. It helps you understand what is structurally possible and what is not.

For Inge, this level of measurement was not a luxury; it was the difference between “maybe” and “we can plan this”.

THE PLAN: STAGED, BESPOKE, AND DELIBERATELY BORING

I am a great believer that the best refractive plans are, on paper, almost boring. They are cautious. They are staged. They use the least risky intervention first, and they leave room for the eye to declare itself at each step.

Inge’s plan was to use the maximum-power ICL to do the heavy lifting, reducing the prescription as much as possible without touching the cornea. Then, once we could measure the residual prescription precisely, and once the eye had healed and stabilised, we would consider a carefully designed laser enhancement to treat what remained.

Because she was also presbyopic, we had to decide how to handle near vision. Inge’s story often gets simplified into “-33 to 0”, but the reality is more nuanced. The goal was not merely to hit a number on a refraction sheet. The goal was to give her functional vision across real life, including distance, intermediate, and near, with a sensible balance of quality and side effects.

That is why the laser stage was not just “LASIK to finish the job”. It was a customised treatment designed to respect her anatomy and her optical needs. In her case, after the ICL stage, the remaining prescription and the presbyopic component were addressed with a Laser Blended Vision approach (PRESBYOND), tailored to what she could tolerate and what she wanted from her vision. The details of the laser platform and programming matter less to most readers than the principle: in extreme cases, you are not choosing a menu item; you are building a plan.

WHAT IT FELT LIKE FOR HER

One of the most striking things about Inge’s account is how quickly her lived experience diverged from her decades of expectation. People who have struggled for years often assume that anything “high-tech” will be dramatic, painful, or frightening. Inge’s experience was the opposite: the process was fast, controlled, and—crucially—she felt looked after.

That psychological shift is not a side note. For someone who has spent 33 years planning their day around contact lenses, it is hard to overstate what it means to wake up and simply see.

She spoke about the liberation of not needing glasses, and about a particular joy that many presbyopes will understand immediately: not needing reading glasses when friends of the same age do. That is not vanity. That is independence.

WHAT THIS STORY IS NOT

It is not a promise that everyone with a very high prescription can, or should, pursue the same pathway. High myopia is not a single entity. Eyes differ in corneal thickness, corneal shape, anterior chamber depth, endothelial cell health, pupil behaviour in low light, retinal status, and many other variables that matter. Some people are excellent candidates for ICL; others are not. Some can safely have a laser enhancement; others should not. Some have retinal findings that change the entire conversation.

It is also not a suggestion that risk disappears with expertise. The point is not that risk is irrelevant; the point is that risk has to be understood, quantified where possible, and managed intelligently. Inge had previously been advised against clear lens exchange because of retinal detachment risk, and I agree with the caution behind that advice. A good refractive outcome is meaningless if the retina later detaches and vision is lost. In high myopes, the retina always deserves respect.

WHY I AM TELLING IT HERE

I am sharing Inge’s journey on Substack because I think there is a wider message hidden inside the headline. The message is that “unsuitable” is sometimes a shorthand for “this clinic doesn’t have a safe pathway for you” rather than “no safe pathway exists”. That is not a criticism; it is simply reality. Not every centre does ICL. Not every centre has the diagnostic infrastructure to plan extreme cases. Not every surgeon is comfortable combining staged approaches. And not every patient needs that level of complexity.

But if you have been living with the belief that you are beyond help, it is worth getting a proper assessment in a place that can evaluate the full range of options. Sometimes the answer will still be “no”—and a well-explained “no” can be a relief. Sometimes the answer will be “yes, but cautiously, and in stages”. And sometimes, as in Inge’s case, it will be an unexpected “yes, we can probably get you all the way”.

I also like telling stories like this because they restore a sense of proportion in the online conversation about refractive surgery. The internet tends to polarise: miracle cures at one end, horror stories at the other. Real refractive practice lives in the middle. It is careful. It is data-driven. It is patient-specific. And when it goes well, it can be quietly life-changing.

A FINAL THOUGHT FOR THE “PROBABLY UNSUITABLE” CROWD

If you are reading this as someone with a very high prescription, or thin corneas, or a history of being told you are not a candidate, I would encourage one thing: do not self-reject based on an old rule of thumb. Get an assessment that is genuinely diagnostic, not just a quick screen. Ask what the constraints are. Ask what options exist within those constraints. Ask what the risks are, and how they are managed. And if the answer is no, make sure it is a no you understand.

Inge spent most of her life assuming she would never see without thick glasses or hard contact lenses. At 47, with a -33 prescription and -5 of astigmatism, she discovered that “never” was not a medical conclusion—it was simply the absence of a plan.

Before getting into the eye optics, here is the simplest analogy I know. Look at the two photographs above, both by world renowned National Geographic photographer Albert Moldvay. On the left, in the vast interior of St Peter’s Basilica in the Vatican, the people in the foreground and the distant windows remain acceptably sharp at the same time: that is a large depth of field. On the right, the child is sharply in focus but the flowers just behind her fall away into blur: that is a small depth of field. In photography this difference is mostly controlled by the lens aperture, but the idea translates beautifully to vision. A conventional optical system has a relatively thin “slice” of perfect focus, so clarity drops off quickly in front of and behind that point, like the shallow-depth portrait. An extended depth of focus (EDOF) approach aims to stretch that single focus into a longer zone of usable clarity, so more distances are acceptably clear without splitting light into multiple distinct focal points, more like the deep-focus basilica scene.

I recently gave an invited talk to a learned society of ophthalmology titled “PRESBYOND: The Original EDOF”. I chose that title because it cuts through a great deal of confusion that patients encounter when they start searching online for presbyopia treatment, reading vision, ageing eyes, “laser for reading glasses”, lens replacement, refractive lens exchange, multifocal IOLs, trifocal IOLs, and EDOF IOLs. The words are familiar; the logic often isn’t.

A quick disclosure, because transparency matters. I developed the concept that was later commercialised as PRESBYOND, and I have a financial interest in it. That said, the core point here is the optical strategy itself. Many surgeons around the world, with no financial connection to PRESBYOND, also favour a corneal approach built around extended depth of focus for a large proportion of presbyopic patients who do not yet have visually significant cataract, because it aims to meet real-world visual goals while keeping risk and side effects low and preserving future options.

WHAT PRESBYOPIA ACTUALLY IS

Presbyopia is the age-related loss of near focusing. The natural lens becomes less flexible over time, and the eye gradually loses the ability to change focus from distance to near. It usually becomes noticeable in the early to mid-forties and progresses over time. People describe it in different ways: needing brighter light, struggling with small print, holding phones further away, feeling that vision is “tired” at the end of the day, or finding that reading glasses have become a constant companion. These are all versions of the same underlying change.

WHY PRESBYOPIA SURGERY FEELS LIKE A MINEFIELD

Once you move beyond reading glasses and varifocals, the surgical landscape can feel confusing because the terminology is often organised around where a procedure is performed rather than what it is trying to achieve optically. Some options are corneal: LASIK, laser eye surgery, monovision, blended vision, PRESBYOND. Others are lens-based: lens replacement, clear lens extraction, refractive lens exchange, cataract surgery, multifocal IOLs, trifocal IOLs, EDOF IOL implants.

The problem is that “cornea versus lens” is not the most useful way to understand your options. The real question is which optical strategy is being used to give you near and distance vision, and what trade-off comes with that strategy in terms of night vision, contrast, depth perception, reversibility, and the ability to refine the result later if needed.

THE THREE OPTICAL STRATEGIES THAT SIT UNDER EVERY OPTION

Almost every presbyopia solution falls into one of three categories.

The first is multifocality. This splits light into more than one focus. It can be done with lenses implanted inside the eye, and it can also be done with corneal laser patterns. Multifocality can deliver strong near vision, but it frequently comes with side effects that are most noticeable in low light, particularly halos and glare around lights, and a reduction in contrast sensitivity. Many patients do well, but the trade-off is real, and it is not something that disappears simply because it is described in reassuring terms.

The second is classic monovision. This sets one eye for distance and the other for near. Some people adapt extremely well, particularly if they have used monovision contact lenses before. The compromise is that each eye is blurred at the “wrong” distance, binocular depth perception (stereopsis) is often reduced, and intermediate vision can be the weak point.

The third is extended depth of focus, or EDOF. In the strict sense, EDOF means stretching a single focus into a longer zone of usable focus, rather than splitting light into multiple distinct focal points. The aim is to increase functional range while minimising the night-vision side effects that are typical of true multifocal optics. The word “EDOF” is sometimes used loosely in the marketplace, so what matters is not the label but the real-world optical behaviour.

WHAT “EDOF” MEANS IN PLAIN ENGLISH

A helpful analogy is a camera. With a wide aperture you get a crisp focus at one distance, but blur appears quickly in front of and behind that point. When you stop the aperture down you increase depth of field: more of the scene is acceptably clear. In eyes, we can create a similar practical effect by shaping the optical system so that focus is elongated rather than razor thin. One mechanism for that is controlled spherical aberration. That sounds technical, but the core idea is simple: instead of all light focusing at one exact point, the system is designed so that focus is extended into a zone, and the brain uses that zone to provide practical clarity across a range of distances.

SO WHAT IS PRESBYOND, REALLY?

PRESBYOND is ZEISS’s platform for what I originally developed as laser blended vision. It is a binocular presbyopia treatment, typically performed with LASIK, that combines controlled extended depth of focus with a small, carefully planned difference between the eyes. This detail matters because it is often mislabelled as monovision. In practical terms it is delivered on ZEISS excimer platforms (for example MEL80 and MEL90, depending on region and configuration). Other manufacturers have introduced related concepts over time, but availability, indications and performance can vary by platform and by prescription range.

PRESBYOND is not classic monovision. Classic monovision is essentially a distance eye and a near eye, with limited overlap. PRESBYOND is designed around overlap, particularly at intermediate distances, so that both eyes contribute meaningfully across daily tasks and the brain can fuse information rather than constantly choosing one eye and suppressing the other. That overlap is the reason many patients describe it as feeling “natural” in day-to-day life, especially for screens, dashboards, cooking, shopping, and general moving through the world.

LENS REPLACEMENT, MULTIFOCAL IOLS, AND THE ABSENCE OF CATARACT

Cataract surgery is one of the most successful procedures in medicine, and when you have a visually significant cataract, lens surgery is absolutely the right solution. Lens-based surgery can also be an excellent option when there is early lens change affecting quality of vision, or when there are specific anatomical or refractive reasons to prefer an intraocular approach. The debate tends to arise when you do not have cataract, but you do have presbyopia, and you are being offered refractive lens exchange (often called lens replacement or clear lens extraction) with a multifocal or EDOF IOL.

If the lens is still clear, removing it is a step that deserves careful thought. It is intraocular surgery, with a different risk profile from corneal laser surgery, even though the absolute risks remain low in experienced hands. It also removes whatever residual focusing range you still have. Many people in their forties and fifties retain a meaningful amount of dynamic accommodation, even if it is no longer enough to read comfortably without help. Taking out a clear lens removes what nature has left you, and then attempts to recreate range of vision with an implant that may introduce its own trade-offs.

There is also the question of predictability. Corneal laser surgery is highly accurate because we are reshaping a known surface with a known optical effect. In lens surgery, even with excellent modern formulas, the final refractive outcome depends in part on where the implant ultimately sits inside the eye. That variable cannot be eliminated entirely.

Then there is optical quality. Multifocal IOLs, and some designs marketed as EDOF IOLs, can split light and produce night-vision symptoms and contrast penalties. Some patients are delighted; others are bothered. The key is that these side effects are not rare curiosities. They are part of the fundamental optics of light-splitting designs.

THE ELEPHANT IN THE ROOM: THREE CLAIMS YOU MAY HEAR

If you speak to enough people about presbyopia surgery, you will encounter three confident statements that sound reassuring, but deserve a more careful, reality-based answer.

The first is “it’s one operation for life, life without glasses”. Lifetime promises are not medical truths. Eyes change with time. The lens continues to age, the tear film and ocular surface can change, pupils change, and cataract becomes likely eventually. A responsible goal is high spectacle independence for everyday life across distance, intermediate and near, with a low side-effect profile, rather than a guarantee that you will never pick up glasses again for tiny print, prolonged low-light reading, or specific high-demand tasks.

The second is “we may as well take out the lens now, you’ll need cataract surgery later anyway”. In the absence of cataract, that can skip an important step. If you can solve the problem on the cornea first, you can keep the eye’s internal structures untouched for as long as they remain healthy. There is also a practical long-term advantage that is easy to understand: if you correct presbyopia on the cornea now and you develop cataract later, you can often choose a straightforward monofocal IOL for the cataract because the corneal optics are already providing extended depth of focus. That can help preserve night-vision quality and avoid feeling pushed into a light-splitting implant later.

The third is “laser doesn’t last, it always needs adjusting”. Laser correction can be very stable. What changes is biology: presbyopia progresses with age, and that is true whichever strategy you choose. The more honest comparison is not “laser sometimes needs a refinement” versus “lens surgery is forever”, because lens pathways can also involve follow-on procedures in real life. The advantage of a corneal strategy, particularly when you are treating a progressive age-related condition, is that it is inherently adjustable. If a small refinement is ever needed, that possibility is part of sensible long-term planning rather than a sign that the original approach was flawed.

WHAT I WANT PATIENTS TO TAKE AWAY FROM THIS

If you are presbyopic and you do not have cataract, you deserve a conversation that starts with first principles: what optical strategy is being proposed, what trade-offs come with it, and why it suits your eyes and your life. Multifocality, classic monovision, and true extended depth of focus are fundamentally different approaches. They can all be done well, and they can all be done badly. The right choice depends on your priorities, your night driving, your tolerance for halos and glare, your work, your hobbies, your ocular surface, and the details of your anatomy and measurements.

The reason I call PRESBYOND “the original EDOF” is not to win an argument about terminology. It is to bring patients back to a simple idea: extend the usable range of vision, preserve binocular function, minimise light-splitting side effects, keep accuracy high, and keep the future flexible, especially if the lens is still clear.

This article is general information, not personal medical advice. The next step, if you are considering presbyopia surgery, is a thorough assessment and an honest discussion that treats your eyes as the centre of the plan, not the marketing category.

What follows is an anonymised version of that conversation, with all identifying details changed. I am sharing it because many people who are scared of laser eye surgery, and those who read online forums full of bad stories, rarely get to see what a detailed, honest consultation actually looks like when you sit down with a refractive surgeon who does this every day.

DOING SURGERY “JUST FOR CONVENIENCE”

His starting point was very simple and very human. He said, “I’m doing this for convenience. I just want to be sure I’m doing the right thing and that I’ve asked all the right questions, because we’re all a bit nervous.” He could already see well with his glasses; the anxiety came from the feeling that he might be taking a serious medical risk for something that is not medically necessary.

I began by reframing the decision. Refractive surgery is elective, but it is not experimental. Between LASIK, PRK and SMILE, tens of millions of procedures have been done worldwide. He was not a test case or a pioneer. The sensible way to think about laser eye surgery is not as a wild gamble but as a comparison of real-world risks: what is the risk of properly performed laser eye surgery versus the risk he has already taken and would continue to take with contact lenses.

If a patient wears daily disposable contact lenses every day for ten years, the cumulative risk of a serious contact lens complication is roughly in the same range as the risk associated with a modern laser eye surgery done once. If they wear extended-wear or reusable lenses, that risk accumulates much faster. In other words, many people have already accepted higher long-term risk for a less reliable form of vision correction, simply because it is familiar and does not feel like “surgery”. The question is not “is there risk?” but “is the level of risk reasonable compared with the alternatives?”

WHAT DOES “RISK OF DAMAGING THE VISION” ACTUALLY MEAN?

There was a lot of vague unease around the phrase “risk to the eyesight”. His parents did not start by saying “blindness”, but that is almost always what they are imagining. So I spelled it out directly.

When we talk about the risk of “damaging the vision” in laser eye surgery, we are not talking about being instantly blind and never seeing again. We are talking about a very small chance that the quality of the vision ends up slightly worse than it was before surgery, even with glasses. That might mean a little bit of ghosting, doubling or fine blurring that cannot be completely corrected back to the original quality with lenses.

That is different from a routine, good outcome where you are much better without glasses, but a tiny bit off target, so that glasses can still make things perfectly sharp again. If glasses can restore your best vision, then nothing has been “damaged”; it is simply not focused perfectly, and we can either live with that or carry out a small adjustment.

For eyes like his, based on his prescription and corneal measurements, there is roughly a two per cent chance that we might want to offer a small enhancement to make an already good result even better. The risk we really focus on – a small, permanent reduction in best-corrected quality of vision that glasses cannot fully fix – is below one in a thousand when the eyes are properly selected, as his were. That is the tiny risk I ask my patients to weigh against the benefits.

“BUT THESE ARE MY EYES – IS THIS REALLY MY RISK?”

He was very clear that he did not want abstract reassurance based on “most people”. He wanted to know what the numbers meant for his specific eyes.

This is crucial. I told him that every risk figure I was quoting was based on data from eyes like his and that I was only offering surgery because his detailed scans, corneal maps and measurements placed him in the safest category. We screen out anyone whose eyes fall into a higher-risk group. The numbers he was hearing were not generic marketing promises; they were what we see when people with his sort of eye go through this pathway. The risk can never be zero, but we can reduce it to a level that is genuinely low.

CHOOSING THE RIGHT CLINIC – SHOULD YOU GET MORE OPINIONS?

He then asked the question that many people quietly think but rarely say out loud: “How do I know this is the right place? A friend recommended you, but I haven’t seen anyone else.”

My answer is always the same. Either you do enough research to be convinced you are in the right place, or you go and see at least one other clinic and compare. I have no interest in people feeling trapped into choosing us because we were the first clinic they saw. If he wanted a second or third opinion, I actively encouraged it.

I also explained the difference between a highly specialised refractive surgery centre and a general provider. The machine itself – the laser – is only part of the story. What really matters is the whole ecosystem: the amount and quality of pre-operative testing, the surgeon’s experience in interpreting that data, and their familiarity with rare or non-routine patterns that most clinics hardly ever see. Many surgeons around the world perform laser eye surgery once a week alongside cataracts, glaucoma and other general procedures. In a dedicated centre, refractive surgery is usually all we do. We design the protocols, we write the textbooks, we publish the data others read.

That does not mean a patient will automatically have a disaster if they go to a high-street chain. Laser eye surgery is so safe now that most people will do well in many places. The real question is whether you want the “standard” approach that works well for the majority, or the “maximal” approach that does everything possible to catch the small minority of unusual eyes before they run into trouble.

IS SMILE REALLY THE RIGHT PROCEDURE – AND WHY NOT JUST DO WHAT DAD HAD?

Because his father had had a surface laser procedure in one eye twenty years earlier, there was a natural tendency to assume that the son should have something similar. He also knew from his own reading that there are several types of laser eye surgery and wanted to understand why I was recommending SMILE.

I explained that LASIK, PRK and SMILE are all excellent, proven procedures when used in the right context. In his specific case, taking into account his prescription, corneal thickness, corneal biomechanics and lifestyle, SMILE was the safest and most appropriate option.

The key difference is that SMILE is a keyhole procedure with no corneal flap. We do not create and lift a flap in the cornea; instead the laser creates a tiny lens-shaped disc of tissue (a lenticule) inside the cornea, which we remove through a very small incision. With no flap, there is no flap to protect and no flap-related complications. The biomechanics of the cornea are preserved more fully, which is particularly helpful in younger patients with moderate to high short-sightedness.

For his eyes, SMILE offered the same visual outcome with an even larger safety margin. If we did not have SMILE, we would have used one of the other established procedures. Because we can offer all options, we can be objective in recommending the one that best fits the patient rather than the one we happen to own a machine for.

RECOVERY: DRIVING, SCREENS, FLYING, SKIING, SHOOTING

Most anxious patients are less worried about the day of surgery itself than about the days and weeks afterwards. This young man and his parents were no different. They wanted to know when he could drive, go back to his computer-based work, fly, ski and return to shooting sports.

I described recovery after SMILE in three phases. The first phase is the overnight healing. You go home, rest and let the surface close over. The second phase is the first day after surgery. By that point almost everyone is vastly better: the vision is not yet crystal clear, because there is still some swelling in the cornea, but it is usually good enough to drive and to work on screens. That swelling then slowly subsides over the next few weeks. During that time the vision can fluctuate slightly as the cornea settles.

By the one-month visit, most patients are seeing very clearly and the fluctuations have faded into the background. The third phase is subtle: a transient feeling of dryness or awareness of the eyes, which tends to fade over the first one or two months. It rarely stops people functioning; it is more a matter of comfort.

On that basis, we normally allow flying forty-eight hours after surgery. Once the first-day check confirms that everything looks as expected, most people can resume activities such as skiing and shooting. The written post-operative instructions are deliberately conservative so that nobody books something demanding before we have actually seen their eyes the next day. A small minority of patients take a bit longer to feel confident with visually demanding tasks, but that is a question of confidence and comfort, not of long-term harm.

WHAT ABOUT AFTERCARE IF WE LIVE IN ANOTHER COUNTRY?

Because the family did not live locally, his mother was very anxious about what would happen after they went home. Would he be on his own if he had a problem? Would he have to keep flying back to the original clinic?

I explained that most of the aftercare is straightforward and revolves around using the prescribed eye drops for a set period. The instructions are simple and do not require any specialist knowledge. The pathway is not designed so that only obsessively careful patients get good outcomes; it is designed so that normal people with normal lives can follow it.

If anything unexpected were to happen back home, we would remain involved. I know refractive surgeons and corneal specialists in many regions, and we can arrange for patients to be seen locally if they need an urgent check. We would share the data, the pre-operative findings and the treatment details. Distance does not mean abandonment; it just means we coordinate care across locations.

DOES A RECENT COLD OR FLU MATTER?

He mentioned that he had recently had a cold or flu and asked whether this could affect the surgery or healing.

I pointed out that if it had any meaningful impact on safety or outcome, it would already be part of our standard history-taking. We are not depending on patients to dream up obscure problems we have forgotten to ask about. As long as he was no longer feverish or acutely unwell, a recent ordinary viral infection would not change how the eye heals.

I used the aeroplane analogy. You do not need to understand the engineering or pilot training to have a safe flight. The safety is built into the system. There is one important difference, however: aviation is governed by strict international standards, whereas laser eye surgery is not. A surgeon can legally perform laser eye surgery one day a week and spend the rest of their time on completely different operations. That is why asking about experience, volume and diagnostic protocols is so important.

HOW LONG DOES LASER EYE SURGERY LAST – IS IT “FOREVER”?

His parents wanted to know: “If this all goes well, does it last forever?” It is a very common question that shows up on forums and in Google searches about laser eye surgery risks.

I explained that the change we make to the cornea is permanent. The cornea does not “wear off” or slowly spring back to its original shape. However, the rest of the eye is living tissue. Over years and decades, the eye can very slowly drift in prescription, just as it would have done without surgery. Later in life the lens inside the eye will age and eventually develop cataract, which would change the focus again.

The key point is that the result is adjustable. If his prescription changes significantly years down the line and he finds it bothersome, we can usually perform a small enhancement, provided the eye remains healthy and there is enough corneal tissue. Laser eye surgery is not a single one-time shot that must be “perfect forever” regardless of what biology does. It is a permanent change that can be fine-tuned if and when the rest of the visual system changes.

LOSING THE “SUPERPOWER” CLOSE VISION

As a moderately short-sighted 21-year-old, he was used to being able to see extremely close up without glasses – almost at the tip of his nose. His mother in particular was worried that he would lose this “superpower” close focus and feel that something valuable had been taken away.

I explained that the ability to see razor-sharp at a few centimetres without glasses is not normal; it is a side-effect of being significantly myopic. It is as if you are walking around with a magnifying glass permanently in front of your eyes. Normal young eyes focus comfortably at a standard reading distance, not a couple of centimetres from the face.

By correcting his myopia we would be removing that built-in magnifier and making him normal. He would lose the extreme close-up “party trick” but gain clear vision through everyday distances without glasses or contact lenses. For the first day or so, the change can feel strange, because his brain has been calibrated to an abnormal focusing range, but it rapidly becomes the new normal.

COULD LASER EYE SURGERY MAKE HIM BLIND?

Eventually his mother voiced the real fear: “I think what I’m really afraid of is that he might go blind from this.” This is exactly the fear that drives many of the horror posts and anxious threads on laser eye surgery forums.

I acknowledged the fear directly. In modern refractive surgery, performed on properly selected eyes with modern technology, the risk of true, complete blindness is extraordinarily remote. In fact, it is so remote that comparing tiny percentages becomes unhelpful. A more meaningful comparison is with other everyday risks we accept without thinking: the risk of a serious car accident this month, for example, is far higher than the risk of going blind from a correctly performed laser eye procedure.

Even glasses are a “risk” in a sense. For someone who is very short-sighted, if their glasses fall off at the wrong moment – on a staircase, on a scooter, on a mountain path – they can injure themselves indirectly because they suddenly cannot see. The point is not that glasses are dangerous, but that there is no such thing as zero risk in life.

If you insist on absolute zero risk, you end up paralysed: too afraid to wear contact lenses, too afraid to cross the road, too afraid even of your current glasses. The real decision is whether the tiny risk of a small permanent drop in best-corrected quality of vision – under one in a thousand in a well-run practice – feels like a reasonable exchange for the benefits of not needing glasses or contact lenses in daily life.

WHY AM I STILL SCARED EVEN WHEN THE NUMBERS SOUND REASSURING?

Towards the end his mother said something that I hear very often: “We understand the statistics. We trust what you’re saying. So why am I still so scared?”

I told her that being scared is normal. Eye surgery feels personal and intimate in a way that hip replacement or dental work often does not. My job is not to talk people into laser eye surgery. My job is to make sure they truly understand the balance between risk and benefit, the alternatives, and what the recovery actually looks like, rather than what the internet tells them. If, after that, someone still feels that their anxiety is too high to proceed comfortably, not having surgery is always a respectable choice.

I also reminded them that if they wanted to see another clinic or two for comparison, they absolutely should. Some clinics that do not have SMILE will be inclined to criticise it, while clinics that do a bit of everything might not have the same depth of specialisation. Seeing that contrast with their own eyes often does more to settle anxiety than any amount of explanation.

DO WE HAVE TO DECIDE TODAY?

Finally, there was the pragmatic question: “If we sign, are we committed? What if he changes his mind or wants another opinion?”

I explained that a consent form is permission to proceed, not an obligation. If he does not sign, we definitely cannot operate. If he does sign and then later decides not to go ahead, that is entirely his choice. This is elective surgery; he could come back in five years if he wanted to.

What matters is that if and when he does choose laser eye surgery, it is a calm, informed decision made with a clear understanding of the very small but real risks, the likely course of recovery, and the alternatives. My role is to be as transparent and direct as possible, to invite every question – including the ones people are embarrassed to ask – and then to step back so that the patient and their family can decide what feels right.

All patient details in this account have been changed to protect confidentiality, but the questions, anxieties and explanations are exactly the kind of exchanges I have every week with people who are scared of laser eye surgery, worried about bad stories they have read online, and trying to decide whether the benefits are worth the risk for them.

When I finished medical school in 1989, laser refractive surgery had barely started. There were no grey-haired experts, no established fellowships, no “gold standard” textbooks. Everyone in the field was starting at roughly the same time. Thirty years later I am one of the grey-haired experts, but I began on exactly the same starting line as the people who had already been consultants for decades. That is one of the unusual things about choosing a young specialty. If you time it right, you can ride the front of the wave instead of paddling to catch up with it.

In this article I want to do three things. First, to show you that all the optics you grudgingly memorised for GCSE or A-level physics is not abstract trivia but the daily language of my job. Second, to demystify laser eye surgery itself – what we are actually doing to the cornea, and why the horror stories you read online are such a distorted picture. And third, to give you a sense of what kind of personality thrives in refractive surgery, because it is not for everyone.

THE EYE AS A PHYSICS PROBLEM

You already know the basics, even if you have not connected the dots yet. Light comes from distant objects as parallel rays. The cornea is the main lens of the eye, about 60 dioptres of power, and the crystalline lens adds roughly 15 dioptres. Remember that a dioptre of power focuses at 1/D metres - e.g. a 4D lens will focus at 1/4 m or 25cm. Together the cornea and lens focus light onto the film at the back – the retina, and particularly the fovea.

Short-sightedness is simply a system with too much power: the optics focus light in front (“short”) of the retina, so by the time the beam reaches the photoreceptors it has already diverged again. Long-sightedness is the opposite problem: the system is not powerful enough, so the focus point ends up behind (“long of”) the retina. Presbyopia is different again; the crystalline lens no longer has the ability to change focus from distance to near - the “zoom” mechanism fails.

Everything we do in refractive surgery is just applied optics. How do you reduce the power of a lens? You flatten it. How do you increase the power? You steepen it. On a cornea, that means changing curvature by removing or reshaping microns of tissue in a controlled way.

The early pioneer of this idea was José Barraquer, a Spanish ophthalmologist in Bogotá. Working with nothing more than trigonometry and an extraordinary amount of ingenuity, he calculated how much tissue you would need to remove from the centre of a cornea of a given curvature to produce a new curvature with a given optical zone. His technique involved slicing off about the front 1/2 of the cornea as a “cap”, freezing it in liquid nitrogen, putting it on a watchmaker’s lathe to sculpt the back surface reshaping the cap, thawing it, and then sewing it back on the bed of the cornea.

The procedure took hours. At one point he used to drive across town with his patient waiting on the table so that he could lathe the cap in his garage and bring it back. By modern standards it was crude, but conceptually he had invented the entire field.

What transformed his idea into a predictable, scalable clinical tool was not better sutures or better microscopes, but lasers. He predicted this, but never was able to use them himself.

FROM TURKEY CARTILAGE TO EXCIMER LASERS

The cornea is transparent, exquisitely organised tissue. If you are going to sculpt it, you cannot burn it and hope for the best. You have to remove carbon atoms without charring, and you have to avoid thermal diffusion into the layers beneath.

This is where the excimer laser appears. Its wavelength, 193 nanometres in the deep ultraviolet, matches an absorption peak of the glycosaminoglycans in the corneal stroma. At that wavelength the tissue absorbs the energy in the top fraction of a micron. The pulse itself lasts a billionth of a second and carries just enough energy to break molecular bonds. Carbon atoms fly off the surface, but there is no time for heat to conduct to the layer below.

The story of how this was discovered is appropriately low-tech. Physicists at IBM were playing with argon-fluoride excimer lasers to etch integrated circuits. An ophthalmologist, Stephen Trokel, heard about it at a cocktail party and asked, “Could this cut cornea?” After Thanksgiving someone brought leftover turkey into the lab. They tried 193 nanometres on turkey cartilage and realised they could groove the surface without burning, whereas green light simply carbonised it. Trokel’s interest was to make incisions in the cornea radially to peroform Radial Keratotomy more accurately, leaving the visual axis of the cornea intact.

If you can remove tissue without scarring, you can sculpt a transparent lens. John Marshall in the UK was the first to patent the idea of using an excimer in the visual axis to reshape the cornea. Modern surface ablation procedures like PRK are a direct descendant of that concept: you remove the epithelium, expose the stroma, track the eye a thousand times per second, and let the laser dance its way through a pre-calculated pattern.

LASIK AND THE RISE OF FENTOSECOND LASERS

You have all heard of LASIK. Conceptually it is Barraquer plus excimer. Instead of freezing a corneal cap and lathing it, we create a thin flap of tissue at the front of the cornea, lift it, reshape the exposed bed with the excimer, then replace the flap. The flap acts like a biological contact lens, protecting the wound.

Originally the flap was created with a microkeratome – essentially a very sophisticated carpenter’s plane. I did the first sixteen thousand LASIK eyes of my career that way. It worked, but it depended on moving steel against tissue, with all the mechanical variability that implies.

Femtosecond lasers changed that. These are infrared lasers that fire unimaginably short pulses. If you blew one femtosecond up to one second, then one second would be thirty-two million years on the same scale. At that timescale you can create a tiny plasma bubble at a specific depth in the cornea, about one micron across, with almost no collateral damage. Line those bubbles up densely in a plane and you have a cleavage plane; in other words, you have cut tissue without a knife.

Today we routinely create flaps with four-micron precision. The cornea is roughly 530 microns thick. We know exactly where we are in that thickness profile, which means the flap thickness is predictable, the residual stromal bed is predictable, and the visual recovery is very fast. Patients feel nothing during the procedure because we use topical anaesthetic. With LASIK, the incision is so small that it seals over in hours.

From a patient’s point of view, the difference between surface ablation and lamellar surgery is dramatic. PRK hurts unless you are good at managing pain - our patients experience next to zero of this, not even discomfort for the most part beacuse we use all the principles learned during my anaesthesia rotation in terms of the different types of analgeiscs to make PRK pain free. You have abraded the most innervated tissue in the body and left a seven-millimetre epithelial defect open for days. Yes, you control pain with bandage lenses, topical and systemic analgesia, but it is still a wound. LASIK, in contrast, is effectively painless. Visual recovery is also faster and, in the right hands, long-term safety is better because there is less risk of surface infection and scarring.

THE SMILE GENERATION

Barraquer predicted the next step long before we could actually do it. He said that one day we would not ablate tissue at all. We would cut two curved planes within the cornea, matching the front and back surfaces of a lens of a particular shape, and then remove that lens through a tiny incision.

That prediction is now routine clinical practice. The technique is called SMILE, small incision lenticule extraction. Carl Zeiss Meditec for decades were the only company that had the optical expertise and the foresight to try to achieve this. A femtosecond laser cuts the front and back surfaces of a lenticule of tissue, and a keyhole incision, often two to three millimetres long. We dissect the upper and lower planes, free the edges, and slide the lenticule out.

If the lenticule is thicker in the centre than at the edge, the cornea becomes flatter centrally once the tissue is removed, and you have corrected myopia. If you design the lenticule as a rugby-ball rather than a sphere, you can correct significant astigmatism and turn an oval cornea into a round one.

We have now treated thousands of eyes this way, up to about –13 dioptres with substantial astigmatism. In a series of four thousand SMILE procedures (up to -9D including up to 6D of astigmatism) I published more than a decade ago, 95 per cent of eyes saw 20/20 without glasses, and around 80 per cent saw as well as or better than they had ever seen in glasses. The proportion losing two or more lines of best corrected acuity was under one in a thousand, and those very few eyes were repairable back to their original level of vision.

So when you read on Reddit that “laser eye surgery does not work” or “you will still need glasses,” remember that you are hearing from a tiny, self-selected fraction of outliers, many of whom could in principle be repaired but either do not know that or cannot access the technology.

THE PRESBYOPIA JUNGLE

If myopic laser surgery is now well-tamed territory, presbyopia correction is still a jungle. Everyone over the age of forty-five loses accommodative amplitude; it is a one hundred per cent penetrance condition. That makes it an enormous potential market as it affects 100% of human beings on the planet, and hence it has attracted a bewildering array of solutions.

At the non-surgical end you have spectacles, multifocal contact lenses and now miotic drops that shrink the pupil to give a pinhole effect. Each has its compromises in terms of contrast, convenience or duration of effect.

You then see clear lens exchange being offered to people with no cataract: essentially doing cataract surgery twenty years early purely to swap a living lens for a multifocal intraocular lens with concentric rings for distance, intermediate and near. For some patients this works very well; many adapt neurologically to the haloes. But about twenty per cent do not adapt and are left with night disturbances which they live with and eventually tolerate - according to studies with the most modern trifocal lenses. Explanting a multifocal lens in a 52-year-old who used to have some accommodation and replacing it with a monofocal is hardly an ideal endpoint, usually a PRESBYOND procedure (see below) would then be required to give them the reading vision they were seeking in the first place.

On the corneal side you see classic monovision, multifocal ablations that slice the cornea into zones, inlays and pinhole devices, scleral expansion procedures, various thermal tightening techniques; the list goes on. Most of these will not survive the next twenty years because presbyopes are a demanding group, and the procedure that wins will need to be safe, accurate, reversible and compatible with future cataract surgery.

The approach I developed and which was implemented by Carl Zeiss into their MEL90 laser as “PRESBYOND Laser Blended Vision”, takes the mono-vision principle but augments it by increasing the depth of field of each eye. One eye is biased towards distance with extended intermediate range, the other towards near with overlapping intermediate. The brain fuses in the middle, so you retain stereopsis and get smooth vision from reading distance to infinity. We have published long-term results across myopes, hyperopes and mixed astigmats up to reasonably high prescriptions.

Again, the important point for you as students is not to memorise brand names but to understand the logic. A solution that deliberately destroys accommodation by removing a clear lens cannot logically be the most physiological first-line option for every 50-year-old who is annoyed with reading glasses.

MYTHS, RISK AND WHY CONTACT LENSES ARE NOT INNOCENT

Several recurrent myths still shape patient and professional attitudes to laser eye surgery. You will hear them in clinics, on wards and probably at family dinners once people know you are in medicine.

“It is very new, better to wait.” In reality, excimer laser corneal refractive surgery has been around for over thirty-five years. Tens of millions of procedures have been done worldwide. That does not mean we can be complacent, but the idea that we have no long-term data is simply false.

“It ruins night vision.” That was a reasonable concern in the era of small, symmetrical optical zones and basic ablation profiles. Modern treatments are larger, wavefront-optimised and often specifically designed to regularise aberrated corneas. For many patients, particularly high myopes, night vision is better with a naked, regularised cornea than it ever was with a contact lens that has been drying and accumulating lipid all day.

“You could go blind.” In theory, yes. Cataract surgery, hernia repair and wisdom tooth extraction can all end in blindness in theory if things go catastrophically wrong. The meaningful question is probability. In our own data, the chance of losing two lines of best corrected acuity from a myopic lamellar procedure was about one in a thousand, and as I mentioned those cases were repairable. Serious infections are vanishingly rare if you maintain standards. By comparison, a contact lens wearer using extended wear lenses accumulates a similar or greater risk of permanent visual loss over months to a few years, simply through chronic insult to the ocular surface and occasional microbial keratitis.

“Contact lenses are safer.” They are not. A daily disposable lens worn correctly is a good solution for many people, but you are still placing a foreign body on the most densely innervated tissue in the body every day, altering its oxygen supply and blinking dynamics. When you look at the epidemiology, the risk of losing vision from contact lens wear over years is higher than the risk from a single well-performed laser procedure.

Your job as future clinicians is not to sell any particular technique but to understand relative risk and communicate it honestly. If you think contact lenses are an acceptable risk, then logically you must also accept that laser eye surgery, done properly, is at least as safe.

FROM “FIRST-WORLD VANITY” TO GLOBAL BLINDNESS

Laser eye surgery is often caricatured as the ultimate first-world vanity procedure, something rich people do so they can go skiing without fogged glasses. There is some truth in that caricature at one end of the spectrum. But there is another end.

In high-income countries, uncorrected refractive error is an inconvenience; you solve it with glasses. In low-income settings, glasses are often unavailable, unaffordable, or fragile luxuries. A farmer who is –4 and cannot afford spectacles is functionally blind. He cannot work, cannot support his family, and his mother will die with her cataract intact because no one can pay for her operation.

About thirty per cent of global visual impairment is due to cataract. Roughly half is due to uncorrected refractive error. My team and I at the London Vision Clinic Foundation working with Geoff Tabin and his organisation CureBlindness have set up laser centres in places like Nepal, Peru and, more recently, Ethiopia, where a small proportion of people who can afford to pay full price effectively subsidise sight-restoring surgery for those who cannot. An eight-minute procedure that heals in hours can be the difference between a family being locked into poverty and a family that can work, pay taxes and fund its own healthcare.

So yes, refractive surgery lives at the luxury end of medicine in London. But it also has the potential to be one of the most powerful economic development tools in global ophthalmology if deployed thoughtfully.

WHAT KIND OF PERSON BECOMES A REFRACTIVE SURGEON?

Finally, a word about personality. You do not need to decide your specialty now. In fact, I strongly advise you not to. Enjoy obstetrics, dermatology, psychiatry, ENT and emergency medicine. Learn as broadly as you can so that whatever you eventually do, you will be a doctor first and a technician second.

If, later on, you find yourself drawn to refractive surgery, recognise that it selects for a particular mix of traits.

You need to enjoy repetition. This is not neurosurgery where every tumour is a different shape and you are constantly improvising. Refractive surgery is closer to being an orchestral musician: the notes on the page are the same every time, and your job is to play the piece beautifully, consistently, over and over again.

At the same time, you must not be rigid. The field moves quickly. Techniques evolve, lasers are upgraded, diagnostic tools improve. If you despise change and cling to the way you were trained as a registrar, you will be left behind and your results will quietly fall behind as well.

You must be calm under pressure. Ninety-nine per cent of cases are routine. The one per cent that are not will try to provoke panic. A suction loss, an incomplete flap, a difficult lenticule, an unusual corneal response – those moments are when your temperament matters most. You cannot afford to freeze or explode. You need to think clearly, improvise within the bounds of safety, and execute a plan while the patient is lying there and the clock is ticking.

And finally, you need to be fanatical about standardisation. The airline industry learned decades ago that checklists, standard operating procedures and continuous learning from near-misses save lives. Surgery is finally catching up. In refractive surgery the vast majority of eyes will forgive sloppy technique. It is the outliers that expose you. If you build your entire workflow around the outliers, the routine cases will look after themselves. If you design your workflow around routine cases, the outliers will eventually hurt someone.

CLOSING THOUGHTS

Refractive surgery sits at an unusual intersection of physics, microsurgery, psychology, economics and ethics. It is one of the purest expressions of “applied optics” you will find in clinical medicine. It is also one of the most misunderstood fields, burdened by outdated myths, variable expertise and a public discourse dominated by extreme anecdotes.

As medical students, you do not need to memorise every acronym or device. What you do need is a clear conceptual model of how the eye focuses light, how we can modify that safely, and how to think about risk in a rational way rather than an emotional one.

If this has sparked your curiosity, come and watch surgery some time. It is one thing to learn Snell’s law from a textbook. It is another to see those equations translated into someone reading a line of tiny print the day after a procedure they could not even have imagined when I was in your shoes.

In this article I want to share with you the technique I use for my patients, for my family, and even for myself. It’s called PRESBYOND. It’s a laser eye procedure designed specifically to restore your reading vision without sacrificing your distance vision, without using implants, and without creating those halos or night-time vision problems that come with older technologies.

Over the years, people have tried many ways to correct presbyopia. One of the simplest is monovision, where one eye is set for distance and the other for near. For some people this works, but many find it uncomfortable or limiting - particularly for tasks like driving at night, using screens, or playing sport.

Other techniques tried to make the cornea (the clear window at the front of the eye) into something like a multifocal lens - different parts focusing at different distances. The problem was that these profiles created optical irregularities, which led to glare, reduced contrast, and often unpredictable results.

PRESBYOND takes a different approach. Instead of splitting the light between zones, we reshape the cornea in a smooth, continuous way that increases what we call “depth of field” - a bit like extending the focus in a photograph so that objects at different distances are all clear at the same time.

It also works by combining a very slight difference between the two eyes: the dominant eye is focused for distance, and the non-dominant eye is set slightly towards reading vision. But unlike monovision, where there’s a sharp difference between the two eyes, in PRESBYOND the eyes overlap in the middle range and work together as a team. That’s why I called it “blended vision” - because there’s no rivalry between the eyes, and your brain doesn’t have to suppress one to use the other.

I’ve found that over 97 percent of patients adapt to this naturally, even those who were completely emmetropic (meaning they never needed glasses before). Vision becomes seamless - distance, computer, reading - all clear, all day, without switching glasses.

The treatment is based on LASIK, so it’s fast, safe, and performed using eye-drop anaesthesia. It takes about ten minutes for both eyes. The laser we use (the ZEISS MEL90) is extremely precise and the planning software calculates the ideal correction based on your prescription and corneal shape. Most patients are back to work the next day, and reading a menu without glasses that same evening.

We can use PRESBYOND to treat patients who are myopic (up to -8.00), hyperopic (up to +6.50), or even those with no prescription but whose near vision is starting to fade.

And what happens if you develop a cataract later on? That’s no problem. Because the vision-enhancing shape is on the surface of the cornea, your cataract surgery can be done exactly the same way as if you’d never had laser. In fact, I’ve also treated patients who already had cataract surgery but still needed glasses - we can use PRESBYOND after lens replacement to give freedom from glasses at all distances.

I even used this approach on the legendary jazz pianist Chick Corea. He needed to be able to see the audience under stage lights, read music at arm’s length, and move freely on stage without visual limitations. PRESBYOND gave him exactly that, and he remained glasses-free until the end of his life.

And yes - I’ve had it too. I’d always had perfect vision, 20/10 in both eyes, but I started to notice I was pulling things farther away to see them clearly. I did what my patients do - I got behind the machine, measured my eyes, and realised I was -0.75D. I had the procedure, and I’ve had a seamless range of vision from far to near ever since. No glasses. No reading struggles. High contrast. No halos. I still don’t have cataracts now at 63, and my night vision remains excellent.

Over the last 20 years, my team and I at the London Vision Clinic have performed over 13,000 PRESBYOND procedures. It’s one of the most satisfying parts of my practice - because the results are predictable, the quality of vision is high, and the freedom it brings to patients is real.

There are other options for presbyopia, including lens replacement surgery with multifocal implants. These are sometimes promoted as a first-line solution. But they carry more risks, especially when performed before there’s an actual cataract. And they don’t always give the same quality of night vision or contrast. PRESBYOND avoids those compromises.

In short, PRESBYOND is for people who want to see again like they used to - who want to live without glasses, read without squinting, and go through the day without switching between three pairs of specs. It preserves what accommodation you still have, and restores what you’ve lost - without entering the eye, without synthetic implanted lenses and without compromising the quality of your vision.

If you’re starting to notice that your arms are getting too short, if you’re juggling reading glasses at work or in restaurants, or if you just want to simplify your visual life - this might be your moment. Feel free to share this with your optometrist or ask your eye surgeon about PRESBYOND. It changed things for me, and for thousands of others. It might just change things for you too.

Monovision remains a safe and valid option, but it has intrinsic limitations. It requires the brain to suppress the blurred image from the non-dominant eye and often sacrifices intermediate vision. For a subset of patients it works well, but others find it intolerable or functionally limiting.

Then came the era of multifocal corneal ablations - attempts to create concentric or asymmetric profiles to simulate a range of focus in one eye. These efforts, which spanned over two decades, ultimately ran into the fundamental problem of high-order aberrations. They reduced contrast sensitivity, induced night-time glare and made outcomes harder to predict. Even the manufacturers eventually scaled back their claims, some recommending such treatments in one eye only due to measurable loss of best spectacle corrected vision of 2 lines in 2% of patients.

PRESBYOND takes a different path. It doesn’t create multiple foci in one eye. Instead, it increases depth of field by inducing a controlled amount of spherical aberration - a type of optical imperfection that the visual cortex can filter effectively without degrading contrast. I often describe it to patients in photographic terms of increasing depth of field of the eye, just as in photographs.

We studied this carefully and developed a model that treats spherical aberration like a drug. There’s a therapeutic window: too little has no effect, too much creates toxicity- in this case, contrast loss or haloes. Within that therapeutic range, though, it allows us to create about 1.5 dioptres of usable depth of focus without losing contrast and without night vision disturbances.

The next insight was to combine this with a small degree of anisometropia. By leaving the non-dominant eye slightly myopic, we extend the near range while maintaining binocular fusion. The non-domninant eye is set to a nominal refraction of -1.50D, but at distance sees 20/60 (as if it was only -0.75D) while at near it sees J1 (as if it was -2.25D) [-0.75D to -2.25D = 1.50D]. The dominant eye is set to plano, so at distance the eye is 20/20, but an near sees as if it was at -0.75D (set to plano with 1.50D surrounding this target [+0.75D to -0.75 = 1.50D], giving near vision. Thus both eyes behave as if -0.75D in the intermediate range and therefore intersect which creates overlap without rivalry - ‘blending’. In my emmetrope cohort - arguably the toughest group to adapt - 97 percent fused binocularly with no loss of stereoacuity at the 1 year mark

.Technically, the procedure uses standard LASIK but only with the ZEISS MEL90 platform, using the Refractive Workplace from ZEISS that implements a custom algorithm which calculates the necessary spherical aberration. The surgeon just enters the patient’s refraction and the preop spherical aberration. The algorith does the rest automatically. We’re not just correcting the myopia or hyperopia - we’re also modulating the spherical aberration itself. And because the ablation profile is smooth and continuous, we avoid the pitfalls of abrupt multifocality which reduce contrast and night vision.

At the London Vision Clinic within the EuroEyes group we have peformed PRESBYOND for over 20 years with oustanding patient satisfaction and near full independence from glasses in nearly all patients. We can treat myopia up to -8.00, hyperopia up to +6.50D (therefore a +5.00D hyperopic patient can have PRESBYOND) and emmetropic presbyopia.

So what happens if the patient develops a cataract after PRESBYOND? No problem. The spherical aberration is already in the cornea, on the visual axis. A simple high-quality monofocal IOL will be planned using a modern IOL formula (e.g. the Barret True K TK) and the depht of field comes from the cornea. Likewise someone who has had cataract surgery beofore but is still in glasses can have PRESBYOND on top: combining monofocal IOL implantation with post-op PRESBYOND is an excellent way of providing vision at all distances without night vision compromises. I actually used that on Chick Corea, with outstanding results. He was able to drive, perform under stage lights, read music at piano stand distance (66 cm) and live entirely free of glasses until the end of his life.

I also operated on myself (well, my associate Glenn Carp did the surgery). As a lifelong emmetrope with 20/10 vision, I was initially in denial about my creeping near blur. Eventually I realised I was focusing at two metres and had a refractive error of -0.75D. I chose PRESBYOND. The procedure was broadcast on the BBC, and I was reading that same evening and have enjoyed 20/10 distance vision, J3 at intermediate and J1+ at near seamlessly for the last 10 years. My contrast sensitivity is still high normal and my Ocular Scatter Index is still very low (0.6 and 0.7 for OD/OS - so I still dont have cataract at 63). I knew then - and still believe now - that there’s no better option. If there had been, I’d have taken it.

In our practice, we’ve performed more than 13,000 PRESBYOND procedures. The outcomes are consistent. Contrast is preserved. Binocular vision is maintained. And the range of focus is genuinely life-changing. While refractive lens exchange remains popular, particularly in certain markets, I believe the trade-offs in probability of 20/20 with one procedure, retention of contrast sensitivity and the adjustability over time make one of the best options for a first-line treatment in patients without cataract.

PRESBYOND offers us a way to preseve remaining accommodation (still present iuntil early 60’s) restore visual function without entering the eye and without compromising quality of vision. It’s quick - ten minutes for both eyes to be completed surgically, healing is measured in hours, visual recovery is almost immediate and patients are going back to work after their postop day 1 visit that same day. In short, it works.