Laser vision correction reduces or eliminates the need for glasses and contact lenses, and for most people the conversation starts with LASIK. But not every cornea suits every procedure, and corneal thickness is one of the first things Dr. Feinerman measures when deciding which option, if any, is right for your eyes.
Patients with thinner corneas face a specific problem: LASIK creates a flap, and that flap uses tissue. PRK, a surface treatment, avoids the flap and preserves more of the cornea, which is why it is often the better option when a cornea is mildly thin. It is not a universal fix. PRK still removes tissue to correct vision, so a cornea that is genuinely too thin for LASIK is often too thin for PRK as well. This article explains where that line falls and what your options are on either side of it.
How Corneal Thickness Decides the Procedure
Clinical data
An average cornea is roughly 500 to 550 microns thick. A LASIK flap typically uses 100 to 120 microns before any correction is applied, and every diopter of nearsightedness treated removes additional tissue beneath it. The U.S. FDA standard is to leave a residual stromal bed of at least 250 microns after treatment, and most surgeons today prefer 280 to 300 microns for long-term safety.
That arithmetic is the whole story. If your cornea measures on the thinner side, or your prescription is high, the tissue committed to a LASIK flap can push the remaining bed below a comfortable margin. Leaving too little tissue behind risks corneal ectasia, a gradual weakening and forward bulging of the cornea that can develop months or years after surgery.
PRK skips the flap. The 100 to 120 microns that LASIK would spend on the flap stay in the cornea, so a patient with a mildly thin cornea and a moderate prescription can often be treated safely with PRK when LASIK would leave too little behind. That is the genuine advantage of surface treatment, and it is why PRK remains a valuable option in this practice.
Key Differences at a Glance
Both PRK and LASIK correct nearsightedness, farsightedness, and astigmatism with the same excimer laser. The differences are in how the cornea is prepared and how it heals.
- Technique: LASIK creates a thin corneal flap and reshapes the tissue beneath it. PRK removes the surface epithelium and reshapes the cornea directly; the epithelium then regrows.
- Tissue use: PRK preserves the tissue a LASIK flap would use, which widens the safety margin for mildly thin corneas.
- Recovery: LASIK vision is typically clear within a day. PRK involves about two days of discomfort and blurry vision for five to seven days while the surface heals, with functional vision within about a week and continued sharpening over the following weeks.
- Flap-related risk: PRK has no flap, so there is nothing to displace in a contact-sport or military setting.
- Enhancement guarantee: the practice’s lifetime enhancement guarantee applies to LASIK procedures (WaveLight® Plus and Wavefront Optimized). Enhancement policies for PRK are discussed individually.
- Visual outcomes: when patients are selected correctly, both procedures deliver clear, stable, long-term vision.
Why LASIK May Not Be the Right Fit for a Thin Cornea
LASIK depends on having enough tissue for a stable flap and a safe residual bed underneath it. In a thinner cornea, three things matter:
- Structural margin. The flap plus the correction must leave at least the minimum residual bed. In a thin cornea with a higher prescription, that margin may simply not exist.
- Prescription size. The higher the prescription, the more tissue the laser removes. A -3.00 D correction in a 500-micron cornea is a very different situation from a -8.00 D correction in the same cornea.
- Long-term stability. Corneal strength is what keeps the correction stable for decades. Preserving it matters more for a 25-year-old than for anyone else, because that cornea has the longest future ahead of it.
When these factors line up against LASIK, PRK is the first alternative Dr. Feinerman considers. When they line up against any tissue removal at all, the conversation moves to a lens-based option.
How PRK Works
PRK, or photorefractive keratectomy, treats the cornea at its surface. Dr. Feinerman removes the outer epithelial layer, reshapes the underlying tissue with the WaveLight EX500 excimer laser, and places a protective contact lens while the epithelium regenerates over the next several days. The procedure takes about 15 minutes for both eyes, and the laser itself is active for only seconds per eye.
Same platform, same surgeon
PRK at Feinerman Vision uses the same WaveLight excimer laser platform and treatment planning as our LASIK procedures. Dr. Feinerman performs every PRK procedure himself and personally handles the evaluation that decides whether PRK, LASIK, or a lens-based option fits your cornea.
When PRK Is Enough, and When It Is Not
This is the distinction the rest of the internet tends to blur, so it deserves its own section.
PRK is often the better option when the cornea is mildly thin. If your measurements fall a little short of what LASIK needs, the tissue PRK saves by skipping the flap is frequently enough to bring the plan back inside a safe margin. These patients do well with PRK and keep the full benefit of laser correction.
PRK is not the answer when the cornea is genuinely too thin. PRK still removes tissue to correct your prescription. If the cornea is thin enough, or the prescription high enough, that even a flap-free treatment would leave too little residual bed, PRK is ruled out for the same reason LASIK is. In that situation, EVO ICL™ is usually the procedure Dr. Feinerman recommends: a lens placed inside the eye, behind the iris, that corrects vision without removing any corneal tissue at all. Thin corneas are not a barrier to it, it is FDA approved for adults ages 21 to 60 with nearsightedness from -3.00 to -20.00 diopters, with or without astigmatism, and the lens can be removed or exchanged by a surgeon if your needs change. Our page on EVO ICL for thin corneas walks through that decision in detail.
PRK is not a workaround for dry eye. Both LASIK and PRK remove corneal tissue and both affect the ocular surface during healing. In a 2026 national registry analysis of nearly 49,000 eyes, dry eye was documented in 16.1% of LASIK eyes and 15.6% of PRK eyes over the first year, and PRK eyes had the higher rate in the one-to-three-month window (Kang S, et al. Am J Ophthalmol. 2026;288:66-74). When dry eye risk is a meaningful concern, Dr. Feinerman typically recommends evaluation for EVO ICL, which removes no corneal tissue and disrupts the corneal nerves far less than LASIK.
Who Should Consider PRK?
PRK suits a specific set of patients, and the evaluation is what sorts them.
- Patients with mildly thin corneas. The core PRK candidate: enough tissue for a safe surface treatment, not enough for a flap plus a correction.
- Contact-sport athletes and military or law-enforcement roles. Without a flap there is nothing to dislodge in a blow to the eye. For patients whose work or sport carries real eye-trauma exposure, PRK is the laser option Dr. Feinerman favors. Our post on PRK for military and pilot vision requirements covers the service-specific rules.
- Patients with mild surface irregularities. Some corneas with minor irregularity or a history of surface injury may be treated with PRK after a detailed evaluation. More complex cases need careful screening, and the recommendation is always individualized.
If none of these describe you and your cornea is healthy and adequately thick, LASIK with WaveLight Plus remains the procedure with the fastest recovery, and it is the one most of our laser patients choose.
Recovery and What to Expect
Patient outcomes
Most PRK patients describe about two days of discomfort and light sensitivity, blurry vision for five to seven days while the epithelium regrows under a protective contact lens, functional vision within about a week, and continued sharpening over the following weeks. The final result is comparable to LASIK; it simply arrives more gradually.
During the first week. Prescription drops, the protective lens, sunglasses outdoors, and a few days away from screens make the difference between a comfortable recovery and an irritating one. Dr. Feinerman calls every patient the evening of surgery and sees you himself the next day.
Return to activity. Because there is no flap, there is no flap to protect. Once the surface has healed and Dr. Feinerman clears you, contact sports, training, and physically demanding work can resume without the flap-displacement concern that follows LASIK patients for a period after surgery.
Long-term vision. Properly selected PRK patients achieve clear, stable vision that holds for years. Regression is uncommon, and when an enhancement is ever needed it is evaluated individually rather than under the LASIK guarantee.
If you are weighing the two procedures on safety specifically, our post Is PRK Safer Than LASIK? compares them on that question.
How the Decision Gets Made at Feinerman Vision
The right procedure for a thin cornea is a measurement question before it is a preference question. Every patient is imaged with the iTrace and Pentacam to map corneal shape and thickness point by point, and Dr. Feinerman reads those scans himself alongside his own examination. From that, one of three paths usually becomes clear: LASIK when the cornea has room to spare, PRK when it is mildly thin, or EVO ICL when it is genuinely too thin for any tissue removal. Dr. Gregg Feinerman evaluates candidacy across every modern option and personally performs LASIK, PRK, EVO ICL, and lens surgery, so the recommendation is never shaped by what the practice happens to offer. He was the first surgeon in Orange County and greater Los Angeles to perform WaveLight Plus LASIK after its FDA approval in 2025, and the first in California to implant the Visian ICL after its 2005 approval.
If you have been told your corneas are thin, that is the beginning of the conversation, not the end of it. Take the candidacy quiz or call (949) 631-4780 to book your evaluation with Dr. Feinerman.
FAQs About PRK & LASIK
Will Dr. Feinerman perform my procedure himself?
Yes. Dr. Gregg Feinerman performs every procedure personally and oversees your care from consultation through recovery, including follow-up after surgery.
What technology does Feinerman Vision use for PRK?
PRK is performed using the WaveLight® EX500 excimer laser, which delivers precise corneal reshaping and consistent visual outcomes.
If I’m not a LASIK candidate, does that mean I still have options at Feinerman Vision?
Yes. Many patients who are not ideal candidates for LASIK can still qualify for PRK or EVO ICL. Your evaluation will determine the safest and most effective option for your eyes.
What makes Feinerman Vision different from other practices?
Patients receive one-on-one care directly from Dr. Feinerman, with no co-management. Every step, from evaluation to follow-up, is handled in-house for better continuity and personalized care.
How do I know I’m choosing the right procedure for my eyes?
Your treatment plan is based on detailed imaging, your vision goals, and Dr. Feinerman’s clinical expertise. The goal is to choose the option that delivers clear vision while protecting long-term eye health.