LASIK complication rates: the numbers behind the risks
How often does LASIK go wrong?
Rarely in a way that threatens sight. In a University of California San Francisco study of 31,921 LASIK patients treated between 2014 and 2016, published in the American Journal of Ophthalmology in 2019, 1.3% had an adverse event and 0.4% a serious one. Across LASIK and PRK combined, 0.37% of eyes lost two or more lines of vision.
Those numbers cover problems surgeons record. Temporary effects such as dry eye and halos are far more common and are better captured by patient questionnaires, which is what the FDA's PROWL studies used. This page collects the published rates in one place; for what each problem feels like and how it is managed, read LASIK side effects and risks.
Keep in mind that a rare event is still possible for any one person. Averages help you compare risks, but they cannot predict your own result: your exam findings, prescription and corneal measurements matter more. Ask your surgeon which of these risks apply most to your eyes.
What are the published LASIK complication rates?
Rates depend on the study, the year and the technology. Older figures often reflect microkeratome blades rather than today's femtosecond lasers.
| Complication | Reported rate | Source |
|---|---|---|
| Any adverse event | 1.3% of patients (serious 0.4%) | Schallhorn et al., Am J Ophthalmol 2019 |
| Loss of 2+ lines of corrected vision | 0.37% of eyes (LASIK and PRK) | Schallhorn et al., 2019 |
| Intraoperative flap complications | 0.7%–6.6%, historical | AAO EyeWiki |
| Diffuse lamellar keratitis (DLK) | 0.4%–4.38% | AAO EyeWiki |
| Epithelial ingrowth | 1%–20% historically; much lower after primary femtosecond LASIK | AAO EyeWiki |
| Flap repositioning (mostly for striae) | 0.35% of femtosecond eyes | AAO EyeWiki |
| Flap displacement | About 0.012% over 12 months | AAO Preferred Practice Pattern 2023 |
| Infection (infectious keratitis) | About 0.035% per procedure (1 in 2,841) | Ophthalmology 2010, 204,586 eyes |
| Early dry eye | 60%–70% | AAO EyeWiki |
| New visual symptoms at 3 months | 43%–46% | FDA PROWL |
| Dissatisfied with vision | 1%–4% | FDA PROWL |
| Retreatment | 1.8% of eyes | Pokroy et al., JCRS 2017 |
Why do older studies quote higher rates?
Because the technology changed. Many alarming figures still quoted online come from the late 1990s and early 2000s, when flaps were cut with a mechanical blade (microkeratome) and lasers were less refined.
EyeWiki notes that epithelial defects during surgery are less common with femtosecond lasers than with microkeratomes, that epithelial ingrowth is considerably lower after primary femtosecond LASIK than in the older literature, and that flap displacement is more frequent after microkeratome flaps. The retreatment study below shows the same trend: within one centre, the two-year retreatment rate fell from 2.58% to 0.38% between 2005 and 2012.
When you compare clinics in Seoul, ask which laser platforms they use for the flap and for the correction; see femto-LASIK vs microkeratome. Newer technology lowers some risks, but it does not replace careful screening, and some problems, such as dry eye, depend more on your eyes than on the machine.
How serious is infection after LASIK?
Rare and usually treatable when caught early. In the 204,586-eye study, 62.5% of infections began within 7 days of surgery. With prompt treatment, 93% of affected eyes reached 20/40 or better and 52.7% reached 20/20, but about 7% stayed below 20/40. That is why the first week's drops, hygiene and water rules matter.
How often is a second treatment needed?
Uncommonly. In a study of 9,177 eyes treated in 2005–2012, published in the Journal of Cataract and Refractive Surgery in 2017, 1.80% had at least one retreatment. Risk was higher with age over 50 and astigmatism over 1.5 D, and the two-year retreatment rate fell from 2.58% to 0.38% over the study period as technology improved. See vision regression after LASIK and LASIK enhancement.
What about corneal ectasia?
Ectasia, a progressive weakening and bulging of the cornea, is one of the most serious LASIK complications. It is rare, and published incidence varies too much between studies to give a single reliable figure. The main known risk factors are a thin or irregular cornea before surgery and a thin residual corneal bed; EyeWiki cites roughly 250–300 µm as the threshold surgeons work to stay above. Good screening is the main protection; see corneal thickness for LASIK.
How do LASIK rates compare with PRK, SMILE and ICL?
| Procedure | Example published figure | Distinctive risk |
|---|---|---|
| LASIK | Adverse events 1.3%, serious 0.4% | Flap complications; dry eye |
| PRK/ LASEK | Adverse events 2.3%, serious 0.7% (PRK, same 2019 study) | Early pain; corneal haze |
| SMILE | No flap, so no flap displacement | Suction loss or difficult lenticule removal during surgery |
| ICL | Temporary pressure rise in 19.9% of eyes 1–6 hours after EVO ICL (FDA study) | Pressure, cataract, endothelial cell loss over time |
More in ICL vs LASIK and LASIK vs PRK.
How should I read these numbers?
Check whether a rate is per patient or per eye, which technology was used, and how long follow-up lasted. Ask your clinic for its own outcomes; a good clinic will discuss them and will turn you down if you are not suitable. Bring questions to ask your surgeon. This is general information; no outcome is guaranteed.
Sources
- Review of Optometry – Adverse events low in refractive surgery (Schallhorn et al., AJO 2019)
- AAO EyeWiki – LASIK complications
- AAO – Large study finds post-LASIK infectious keratitis rare
- ESCRS – Myopic LASIK retreatment: incidence and associations (JCRS 2017)
- AAO EyeNet – PROWL symptoms and satisfaction
- FDA – What are the risks?
Key facts
- Any adverse event: 1.3% of LASIK patients; serious 0.4% (Am J Ophthalmol, 2019)
- Infection: about 0.035% of procedures (Ophthalmology, 2010)
- Flap displacement: about 0.012% of eyes over 12 months (AAO)
- Retreatment: 1.8% of eyes in a 9,177-eye study (JCRS, 2017)
- Dissatisfied with vision: 1–4% (FDA PROWL)
- Plain-English overview: LASIK side effects and risks
Related guides
Independent directory. Prices are typical ranges reported by Seoul clinics and change often. Always confirm a written quote and get a full eye exam before booking. This page is general information, not medical advice.
FAQ
Frequently asked questions
What percentage of LASIK surgeries have complications?
In a large 2019 US study, 1.3% of LASIK patients had an adverse event and 0.4% a serious one. Temporary effects such as dry eye are much more common.
What is the most common LASIK complication?
Dry eye, reported in 60–70% of patients early after surgery. It usually improves over months.
How common is infection after LASIK?
About 0.035% of procedures, or roughly 1 in 2,841, in a study of more than 200,000 eyes. Most infections started in the first week.
What are the chances of needing LASIK again?
About 1.8% of eyes in a 9,177-eye study needed retreatment. The risk was higher over age 50 and with more astigmatism.
Is LASIK riskier than SMILE or PRK?
Each has different risks. PRK had a slightly higher adverse event rate than LASIK in the same 2019 study, and SMILE avoids flap problems but has its own surgical risks.
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