Laser Eye Surgery - Annie Grace Hu

I always hear that laser eye surgery is getting better every year, but is that true?

When my brother began looking into laser eye surgery for himself, I began to investigate and here is what I found.

Terminology

PRK (photorefractive keratectomy, 1988)
The original, with no flap. The surgeon removes the thin outer skin of the cornea, lasers the surface, and the skin grows back over a few days. Slower and more uncomfortable to recover from, but still used for thin corneas and for people who might get hit in the eye (police, military).

LASEK (laser-assisted subepithelial keratectomy)
The thin outer skin is loosened with alcohol, moved aside, and laid back down after the laser. Only that thin skin moves, and it grows back on its own, so nothing gets cut into the cornea itself the way LASIK's flap does. Less common now.

LASIK (laser-assisted in situ keratomileusis, approved 1999)
The one people mean by "laser eye surgery." A hinged flap is cut in the cornea, folded back, the tissue underneath is lasered, and the flap goes back down. Fast recovery, which is why it took over.

SMILE (small incision lenticule extraction, 2016)
No flap. The laser cuts a lens-shaped disc inside the cornea and the surgeon slides it out through a small cut.

EVO ICL (implantable collamer lens)
A lens is implanted inside the eye and nothing is removed from the cornea. For strong prescriptions.

(Refresher on how your eyes focus in appendix A.)

What already improved

1988 First laser reshaping of a living human eye (PRK)
1989 to 1990, then 1999 LASIK: patented, first performed, then FDA-approved The flap technique was patented by Peyman in 1989 and first done on human eyes by Pallikaris around 1990. The flap is cut with a blade at first. FDA approval in 1999 is when it went mainstream, with much faster recovery than PRK.
2001 Bladeless "femtosecond" flap cutting A laser cuts the flap instead of a blade, so the flap is thinner and more predictable.
2002 Wavefront-guided custom treatments The laser corrects a detailed map of your eye instead of just your glasses prescription. Better night vision, fewer halos.
2016 SMILE FDA-approved
2022 EVO ICL implantable lens
2024 SMILE Pro The updated SMILE laser cuts the disc in about a third of the time.

A 2016 review of 97 studies (almost 68,000 eyes) found 99.5% of patients ended up 20/40 or better (good enough to drive without glasses) and only about 1% were dissatisfied.¹

Downsides

LASIK: the flap never fully heals. A cadaver study measured the healed flap at about 2% of normal corneal strength, and there are rare case reports of flaps knocked loose by trauma to the eye decades later.² Debris and cells can also get under the flap and cause inflammation, mostly around the time of surgery.³ Try really hard not to get pepper sprayed. Fine particles can get lodged under the flap and inflame it, which is why some police and military eye-care guidance nudges people toward the flapless procedures.⁴ Don't ask me how I know.
SMILE: less dry eye in the first months than LASIK, and the cornea may stay sturdier (studies in real eyes are mixed). Not approved for farsightedness in the US yet, and touch-ups are trickier.⁵

What's still coming

Cross-linking combined with LASIK Strengthening the cornea in the same session as LASIK, meant to lower the risk of a rare corneal weakening complication. Whether it prevents it isn't proven yet.⁶ already in use / in trials
Refractive index shaping A laser changes how the cornea bends light without cutting or removing any tissue.⁷ early human trials
Electromechanical reshaping A small electric current briefly softens the cornea so it can be molded to shape, then it re-stiffens. No laser, no tissue removed, which I love the sound of.⁸ rabbit eyes in a lab only, per the 2025 report

The American Chemical Society's short video on the electromechanical reshaping work (Aug 2025).
Vision-improving eye drops Drops for reading vision, which usually starts to go around age 45, already exist (Vuity 2021, Qlosi 2023, Vizz 2025), but they work by shrinking your pupil for a few hours. They don't reshape anything and won't fix nearsightedness.⁹ first-gen approved; reshaping drops are far off

I don't know when any of these new techniques will arrive, but I am looking forward to it! For myself, I am choosing to wait because I believe the advancements are worth waiting for, and my vision is mild.

Appendix

A. How your eyes focus.

The cornea is the clear dome at the front; the retina is the layer at the back. Image: Blausen.com staff (2014), Medical gallery of Blausen Medical 2014, CC BY 3.0.

Your cornea and the lens behind it bend incoming light so it lands exactly on the retina. Blurry vision is usually about where that light comes into focus.

Normal
Light lands right on the retina.

Nearsighted (myopia)
Eyeball too long, so light focuses in front of the retina. Far-away things are blurry.

Farsighted (hyperopia)
Eyeball too short, so light focuses behind the retina. Close-up things are blurry.

Astigmatism
Cornea curved unevenly, so light focuses at more than one point.

Glasses and contacts bend the light before it reaches your eye. Laser surgery instead changes the curve of the cornea itself, which does most of your eye's focusing.

B. The timelines Claude made me.

Show screenshots

Screenshot of Claude's answer: a timeline of past laser eye surgery milestones from 1999 LASIK approval through 2025 ray-tracing LASIK, with rough success-rate labels. — Claude's version of the past. The success-rate numbers are rough.

Screenshot of Claude's predicted near-term improvements, 2026 to 2030, including AI surgical planning and new flapless procedures. — Claude's near-term guesses, with made-up dates.

Screenshot of Claude's further-out predictions, 2029 to 2040, sorted by confidence, from cross-linking combos to smart contact lenses. — Claude's far-future guesses, sorted by how confident it is.

References

¹ Timeline dates from the American Academy of Ophthalmology's "A Look at LASIK Past, Present and Future", Peyman's 1989 LASIK patent (US 4,840,175), and their SMILE explainer. Outcomes: Sandoval et al., "Modern laser in situ keratomileusis outcomes," Journal of Cataract & Refractive Surgery (2016): 99.5% at 20/40 or better uncorrected, 90.9% within ±0.5 D of target, about 1.2% dissatisfied. ↩

² Schmack et al., "Cohesive tensile strength of human LASIK wounds," Journal of Refractive Surgery (2005), which measured central flap adhesion at roughly 2% of normal cornea and the flap edge at about 28%. See a case report of a flap dislocated 24 years later; these are rare and take trauma to the eye. ↩

³ Overview of LASIK flap and interface complications (epithelial ingrowth, diffuse lamellar keratitis): Moshirfar et al., 2014. ↩

⁴ Review of Optometry, "LASIK, LASEK or PRK for Cop?", on why officers who might face pepper spray have been steered toward flapless procedures. The one direct study I could find, a 2002 Journal of Refractive Surgery letter, reported that LASIK eyes held up fine after pepper spray exposure in military training. ↩

⁵ American Academy of Ophthalmology on SMILE, plus a peer-reviewed comparison of SMILE and LASIK: Titiyal et al., 2018. ↩

⁶ On LASIK Xtra: Review of Ophthalmology, "LASIK Xtra: Is It for Everyone?", and a review of cross-linking after refractive surgery: Corneal Collagen Crosslinking for Ectasia After Refractive Surgery (2024). Studies show good stability so far but have not directly shown it reduces the ectasia rate. ↩

⁷ Laser-induced refractive index change (LIRIC), from the University of Rochester and Clerio Vision: the Huxlin Lab overview and the first-in-human results (ARVO 2019). ↩

⁸ American Chemical Society, "An alternative to LASIK, without the lasers" (August 2025), and the earlier proof-of-concept in ACS Biomaterials Science & Engineering. ↩

⁹ FDA approvals: Vuity (Oct 2021), Qlosi (2023), Vizz (July 2025). For slowing kids' nearsightedness, low-dose atropine drops are used off-label; see the AAO's overview. ↩