Laser eye surgery can help clear up blurry vision, but new guidelines on the procedure emphasize that not every spectacled person is a candidate.

LASIK eye surgery is often successful in improving the common vision problems of near-sightedness, far-sightedness and astigmatism. But before going under the laser, patients should be screened for problems that make them non-candidates and should have realistic expectations about their post-surgery vision, according to guidelines issued by the American Society of Cataract and Refractive Surgery (ASCRS).

LASIK (for laser assisted in situ keratomileusis) is performed about 1.5 million times a year in the US. The procedure corrects vision problems by reshaping the cornea, the clear covering over the front of the eye.

While it is generally safe and major complications leading to vision loss are rare, LASIK is not for everyone, according to the ASCRS.

For example, "non-LASIK candidates" include people with eye diseases like cataracts, advanced glaucoma and disorders marked by thinning of the cornea. A measurement of the eyes' corneal thickness is among the examinations that should be done before LASIK surgery, according to the new guidelines. Other steps include measuring pupil size, examining the cornea for abnormalities and measuring the ability of the muscles to align the eyes.

The guidelines also cite factors that make a patient a "less-than-ideal" candidate for LASIK. People who have immune system disorders or are taking drugs that suppress the immune system fall into this category, as post-surgery healing may be hindered. Patients with a history of dry eyes are also not ideal candidates because this problem can worsen after LASIK.

Besides dry eyes, other potential side effects of LASIK include seeing "starbursts" and "halos" and having trouble driving at night.

Above Stoplight at Close Range in patient with LASIK surgery gone bad
Above Right Massive Starbursts in patient with LASIK surgery gone bad
Right Normal Vision

According to the ASCRS guidelines, patients should be fully informed of these side effects before surgery and should have realistic expectations about their post-LASIK vision.

LASIK cannot provide perfect vision every time for every patient. In addition, repeat procedures may be necessary, and even then, a person's vision may not be as good as it was with corrective lenses.

Eye Surgery Education Council