Problems with the corneal flap after surgery sometimes make further treatment necessary. There is a chance, though small, that vision will not be as good after the surgery as before, even with glasses or contacts.

Some people experience side effects after LASIK that usually disappear over time. These side effects may include hazy or blurry vision; difficulty with night vision and/or driving at night; scratchiness, dryness and other symptoms of the condition called dry eye; glare, halos or starbursts around lights; light sensitivity; discomfort or pain; or small pink or red patches on the white of the eye. In a small minority of patients, some of these effects may be permanent.

Sometimes a second surgery, called a retreatment, may be needed to achieve the desired vision correction. This is more likely for people who were more nearsighted, farsighted, or had higher astigmatism before LASIK -- those whose vision originally needed more intensive correction. Approximately 10.5 percent of LASIK patients in the United States require a retreatment.

Results Overwhelmingly Favorable

While LASIK outcomes overwhelmingly are favorable, remember that as with any surgery, risks of complications still exist. Fewer than 1 percent of patients still experience serious and ongoing vision problems following LASIK, because no surgical procedure is ever risk-free.

Even people who have excellent uncorrected visual acuity after LASIK based on eye chart testing still can have bothersome side effects. For example, it is rare but possible that you may see 20/20 or better after LASIK but still have symptoms such as double vision, unresolved dry eyes or difficulty seeing at night because of glare or halos around lights. 

When you sign the LASIK consent form provided by your eye surgeon prior to surgery, you should do so with a full understanding that, even in the best of circumstances, a slight chance exists that something unintended could occur.