LASIK Risks, Complications, and How Surgeons Mitigate Them

Elective surgery should be approached with clear eyes. Here is what the data actually says about LASIK risks, how they compare to alternatives, and what modern surgical practices do to minimize them.

LASIK complication rates by the numbers

Understanding risk starts with understanding frequency. The following rates are drawn from large-scale meta-analyses and FDA studies conducted over the past two decades.

Common, usually temporary effects:

• Dry eye symptoms: Approximately 20-40% of patients in the first month. The vast majority resolve within 3-6 months. Persistent dry eye beyond 12 months occurs in roughly 1-5% of patients depending on pre-existing risk factors and the study definition used.
• Night halos and glare: Reported by 15-30% of patients in early weeks. Clinically significant symptoms that persist beyond 6 months are seen in approximately 1-3% of patients.
• Fluctuating vision: Very common in the first 1-2 weeks; nearly universal and not classified as a complication.

Uncommon but documented risks:

• Under/overcorrection requiring enhancement: 2-5% of eyes depending on initial prescription severity. Higher myopia and hyperopia carry higher rates.
• Epithelial ingrowth under the flap: Occurs in roughly 0.5-2% of primary LASIK procedures. Most cases are mild and require no intervention; visually significant ingrowth requiring treatment is under 0.5%.
• Diffuse lamellar keratitis (DLK): Reported in 0.5-3% of cases depending on the era and laser platform. Nearly all cases resolve with topical steroids when caught early at day-one follow-up.

Rare but serious complications:

• Infection (microbial keratitis): Approximately 1 in 2,500 to 1 in 5,000 cases (0.02-0.04%). This is substantially lower than the annual infection risk for daily contact lens wearers.
• Corneal ectasia (progressive thinning/steepening): Estimated at 0.04-0.6% historically. Modern screening with corneal tomography and biomechanical testing has driven this toward the lower end of that range.
• Flap complications requiring intervention: Less than 0.5% with femtosecond laser flap creation, compared to approximately 1-2% with older microkeratome technology.
• Permanent, significant vision loss: Less than 0.1% in contemporary studies. This includes all causes such as infection, ectasia, and severe irregular astigmatism.

The PROWL studies: what the FDA found

The FDA’s PROWL (Patient-Reported Outcomes With LASIK) studies, published in 2014 and 2017, were landmark prospective investigations specifically designed to measure how patients experience LASIK outcomes, not just clinical measurements on a chart.

Key PROWL findings:

• Overall satisfaction exceeded 95%. The vast majority of participants reported being satisfied or very satisfied with their results.
• Less than 1% of participants reported significant difficulty with daily activities due to visual symptoms after surgery.
• New visual symptoms did occur. About 30-40% of participants reported at least some new visual symptoms (halos, glare, dry eye) at 3 months. However, only a small fraction rated these symptoms as severe or very bothersome.
• Pre-existing symptoms matter. Patients who already experienced dry eye or visual symptoms before surgery were more likely to report persistent symptoms afterward. This underscores the importance of thorough pre-operative assessment.
• The studies led to improved screening recommendations. The FDA used PROWL data to refine patient selection criteria and informed consent processes.

The PROWL studies are often cited by both proponents and critics of LASIK. The balanced reading is that the procedure works well for the vast majority, but a small percentage of patients do experience bothersome symptoms that persist, making candidate selection critically important.

LASIK risks in context: comparison with alternatives

No medical decision exists in a vacuum. Choosing not to have LASIK means continuing with glasses or contact lenses, both of which carry their own risks and costs.

The cumulative risk comparison is worth emphasizing: because LASIK is a one-time procedure, its risk profile does not compound over time, while the infection risk from contact lens wear accumulates with each year of use.

Long-term safety data: 10+ year studies

Several long-term studies have followed LASIK patients for a decade or more:

• Alió et al. (2015) followed wavefront-optimized LASIK patients for 10 years and found stable refractive outcomes and high satisfaction, with no late-onset ectasia in properly screened patients.
• O’Brart et al. (2014) published 18-year follow-up data showing that while some myopic regression occurred (approximately 0.5-1.0 diopters of drift over two decades), the vast majority of patients still functioned without glasses for distance vision.
• Regression rates: Studies consistently show that 85-95% of eyes remain within 1 diopter of the intended correction at 10 years. Low-to-moderate myopia has the most stable outcomes; high myopia (-8.00 and above) shows more regression.
• No evidence of accelerated cataract formation or other long-term ocular disease attributable to LASIK has been found in any major study.
• Corneal biomechanical stability has been confirmed in long-term studies when adequate residual stromal bed thickness is maintained during the original procedure.

The long-term data supports the conclusion that LASIK outcomes are durable for the overwhelming majority of patients when proper screening criteria are met.

How modern technology reduces risks

The technology landscape in refractive surgery has advanced substantially since LASIK’s early years. Each generation of improvement has driven complication rates lower.

Femtosecond laser flap creation: Replacing the mechanical microkeratome with a femtosecond laser for flap creation reduced flap-related complications (irregular flaps, buttonholes, free caps) by roughly 50-75%. Flap thickness is now programmable and reproducible to within a few microns.

Wavefront-guided and topography-guided treatments: These platforms create a treatment profile customized to the individual eye’s optical aberrations or corneal shape, rather than applying a generic correction. Studies show reduced induction of higher-order aberrations (the optical imperfections that cause halos and glare) compared to conventional treatments.

Real-time eye tracking: Modern excimer lasers track eye position at speeds of 500-1,000+ Hz and adjust the laser delivery in real time. This compensates for involuntary eye movements during treatment and improves centration accuracy.

Advanced screening technology: Corneal tomography (Pentacam, Galilei) maps the front and back surfaces of the cornea, detecting early ectasia risk patterns that topography alone might miss. Some clinics now incorporate corneal biomechanical measurements (Corvis ST, ORA) for an additional layer of screening.

Improved nomograms and AI-assisted planning: Surgeons now have access to large datasets and software-assisted planning tools that refine treatment parameters based on thousands of prior outcomes.

Your role in safety

Patient actions meaningfully affect outcomes:

• Share your full medical and eye history, including all medications (especially isotretinoin, amiodarone, and immunosuppressants), prior eye surgeries, and autoimmune conditions.
• Follow contact lens washout timelines before measurements. Soft lenses: typically 1-2 weeks off before evaluation. Rigid gas-permeable or hard lenses: 3-4 weeks or more. Your surgeon may require longer discontinuation periods depending on lens type.
• Use prescribed drops consistently. Antibiotic drops prevent infection. Anti-inflammatory drops reduce healing-related haze. Artificial tears manage the dry eye that is nearly universal in early recovery.
• Avoid eye rubbing, particularly in the first 3 months. Flap dislocation from trauma is rare but preventable.
• Attend all follow-up appointments, especially the day-one visit where DLK and other early complications are screened.

Signs that need a call

Some symptoms after LASIK are normal (mild burning, light sensitivity, tearing in the first hours). Others require urgent evaluation:

• Increasing pain that worsens rather than improves after the first 4-6 hours
• Sudden drop in vision after an initial period of improvement
• A curtain-like shadow or persistent dark area in your visual field
• Pus-like or colored discharge from the eye
• A new large floater or flashes of light, which may indicate retinal issues unrelated to the corneal procedure but still require evaluation

When in doubt, call your surgeon’s office. Most clinics provide after-hours emergency contact information. Early intervention dramatically improves outcomes for nearly every complication.

Putting risk in perspective: what the data means for your decision

Understanding complication statistics requires context. A 20% rate of temporary dry eye sounds high in isolation, but consider that virtually all of those cases resolve within 3-6 months with standard artificial tear therapy. Meanwhile, the less-than-0.1% rate of serious, permanent complications places LASIK among the safest elective surgical procedures performed in the United States.

The question is not whether LASIK carries zero risk, because no medical intervention does. The question is whether the risk profile is acceptable relative to the benefits and relative to the ongoing risks of your current vision correction method. For a contact lens wearer, the cumulative 10-year infection risk from daily lens wear (estimated at 0.4-2%) meaningfully exceeds the one-time risk profile of LASIK. For a glasses wearer with no desire to be free of frames, the calculus is different.

A thorough pre-operative evaluation identifies patients who face elevated risk. The surgical community has become increasingly conservative about candidate selection, which is one reason complication rates have continued to decline even as procedure volumes have remained high. If a surgeon tells you that you are not a good LASIK candidate, that is the safety system working as intended, not a reason to find a surgeon who will say yes.

Choosing a safer path

In some cases, LASIK may not be the safest choice for a particular patient. Alternative procedures exist for good reason:

• PRK (photorefractive keratectomy): No flap creation, eliminating all flap-related risks. Often recommended for thinner corneas, patients with occupations involving combat or contact sports, or certain corneal surface irregularities.
• SMILE (small incision lenticule extraction): A flapless procedure that may offer advantages for dry eye outcomes. Suitable for myopia and myopic astigmatism.
• ICL (implantable collamer lens): Does not remove corneal tissue. Often preferred for very high myopia or patients with thinner corneas who are not candidates for corneal laser procedures.
• Lens-based procedures (refractive lens exchange): May be appropriate for patients in their 50s and 60s who are approaching cataract age.

Candidacy screening is specifically designed to recommend the safest and most effective option for each individual. A surgeon who presents alternatives when LASIK is not ideal is demonstrating good clinical judgment. For a deeper look at how surgeons determine candidacy, see our LASIK candidacy checklist.

Related resources

• LASIK vs. PRK vs. SMILE: Which Procedure Fits Your Eyes?
• Managing Dry Eye Before and After LASIK
• How to Choose a LASIK Surgeon: Credentials, Volume, Tech
• LASIK Center Accreditation and Safety Checkpoints
• LASIK Recovery Timeline: Hour-by-Hour to Month 3
• Find a LASIK Center Near You