LASIK has a 96% patient satisfaction rate, the highest of any elective procedure. But that still leaves a meaningful number of people who aren’t fully happy with their results, and the ways things can “go wrong” range from mild annoyances that fade within months to rare but serious complications that permanently affect vision.
Here’s what the numbers actually look like, broken down by the type of problem.
New Visual Symptoms After Surgery
The most common issue isn’t blurry vision. It’s new visual disturbances that weren’t there before. The FDA’s own clinical studies found that up to 46% of patients who had zero visual symptoms before LASIK reported at least one new symptom three months after surgery. The most frequent was halos, those rings of light around headlights and streetlights at night. Up to 40% of participants who never had halos before developed them after the procedure.
That sounds alarming, but context matters. For the vast majority, these symptoms are mild and don’t interfere with daily life. Less than 1% of participants in the FDA studies experienced “a lot of difficulty” with or inability to do their usual activities because of starbursts, ghosting, halos, or glare. So while nearly half of patients notice something new, only a tiny fraction find it disruptive enough to affect how they live.
Dry Eyes: The Most Common Side Effect
Dry eye is practically universal in the short term. About 50% of patients have dry eye symptoms one week after surgery, dropping to around 40% at one month and 20% to 40% at six months. For most people, this resolves with artificial tears and time.
Chronic dry eye lasting more than a year is far less common. One study tracking long-term outcomes found the incidence of persistent post-LASIK dry eye was 0.8%. That’s roughly 1 in 125 patients. If you already have dry eyes before surgery, your risk is higher, which is why surgeons screen for this beforehand.
Vision That Drifts Back Over Time
LASIK doesn’t always hold forever. A 10-year follow-up study found that 35.8% of eyes required retreatment over the decade. That doesn’t mean those patients had bad outcomes initially. Vision can regress gradually, especially in people who were highly nearsighted to begin with. The good news is that retreatment (an enhancement procedure) is straightforward and typically covered by the original surgeon’s warranty if done within a certain window.
In that same study, average uncorrected vision was excellent at one month and only slightly decreased at the 10-year mark. So while some regression is common, it’s usually modest rather than a return to square one.
Serious Complications Are Rare
The complication people fear most is corneal ectasia, a progressive bulging and thinning of the cornea that can seriously impair vision. The incidence in clinical studies is around 0.17%, or roughly 1 in 600 eyes. The biggest risk factor is removing too much corneal tissue during the procedure, which is why preoperative measurements of corneal thickness are critical. Patients with thin corneas or the early signs of a condition called keratoconus are at significantly higher risk and should not have LASIK at all.
Other serious flap-related complications, like incomplete cuts, tissue displacement, or infection, have become substantially less common with modern technology.
Modern Lasers Have Reduced Risk
The shift from blade-based to bladeless (femtosecond laser) LASIK has eliminated several categories of complications entirely. Older mechanical blades could malfunction, jam, or lose suction mid-cut. According to the American Academy of Ophthalmology, these complications are either impossible or clinically insignificant with femtosecond lasers.
The precision difference shows up in outcomes. One center reported that the percentage of eyes achieving 20/20 or better uncorrected vision jumped from 80% with mechanical blades to 93% with femtosecond lasers. Randomized studies also found fewer optical distortions with laser-created flaps compared to blade-created ones. Earlier generations of femtosecond lasers had their own issues, including inflammation and light sensitivity, but current systems operate at higher speeds with lower energy, which has largely resolved those problems.
Who Faces Higher Risk
LASIK complications aren’t random. Certain patients are significantly more likely to have a poor outcome, and responsible surgeons will decline to operate on them. The FDA lists several factors that make someone a poor candidate:
- Unstable prescription: If your glasses or contact lens prescription changed in the past year, your eyes are still shifting and the correction may not hold.
- Thin corneas: Not enough tissue to safely reshape can lead to serious structural problems, including ectasia.
- Large pupils: People with naturally large pupils, especially in dim light, are more prone to halos, glare, and starbursts after surgery.
- Dry eye disease: Pre-existing dry eyes will almost certainly get worse, at least temporarily.
- Autoimmune conditions or diabetes: Diseases that affect healing (lupus, rheumatoid arthritis, HIV, uncontrolled diabetes) increase the risk of complications.
- Keratoconus: This corneal thinning disorder is a firm contraindication for LASIK.
- Age under 18: No lasers are FDA-approved for minors, and people in their early 20s may still have shifting prescriptions.
- Contact sports: Boxing, wrestling, and martial arts create ongoing risk of flap dislocation from impact to the face.
Pregnancy, breastfeeding, and certain medications (steroids, retinoids) can also cause temporary vision fluctuations that make LASIK results unreliable.
Putting the Numbers in Perspective
The honest summary: most people who get LASIK are happy with the results, and the procedure is genuinely one of the safest elective surgeries available. But “safe” doesn’t mean “risk-free.” Nearly half of patients notice some new visual symptom like halos or glare, though very few find it bothersome enough to affect daily life. About 1 in 125 develop chronic dry eye. Roughly a third may need a touch-up procedure within 10 years. And serious, vision-threatening complications like ectasia occur in fewer than 1 in 500 cases.
Your individual risk depends heavily on your eye anatomy, prescription stability, and overall health. The single most important thing you can do to avoid a bad outcome is to choose a surgeon who will honestly tell you if you’re not a good candidate, even if that means turning you away.