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Keeping an Eye on Side Effects of Laser Eye Surgery

May 16, 2000 -- Tired of uncomfortable contact lenses? Annoyed by the slip-sliding of glasses? You would consider laser eye surgery to correct your vision, but you've heard there can be distracting side effects, like seeing halos and starbursts around lights. How common are they, and which type of surgery will give you the best results with the lowest risk of side effects? A new study, in the May issue of the journal Ophthalmology, may help open your eyes.

"The side effect that the study specifically focused on were these optical symptoms that are not captured with conventional, 20/20 vision testing," study co-author Roger Steinert, MD, tells WebMD. "When you go on the Internet, you see lots of comments on halos and glare and [double vision]. ... Those kind of visual complaints, we know they occur, and we hear about them from patients. What this study looked at is whether or not there was a difference between LASIK and PRK [two popular types of laser surgery] in the frequency of these complaints." Steinert is a consultant for Summit Technology Inc., which manufactures lasers for eye surgery.

Steinert and colleagues asked 220 patients with moderate to severe nearsightedness to fill out a questionnaire about certain side effects they experienced before and six months after undergoing one of two procedures: the older PRK or the more recently approved LASIK.

In both procedures, the surgeon uses a laser, which produces a beam of ultraviolet light in pulses that last only a few billionths of a second, to remove a microscopic amount of tissue from part of the eye called the cornea. "Basically, you are using the ... laser to reshape the cornea," Michael Gordon, MD, tells WebMD. "They are both effective, but there is more scarring and discomfort and greater delay in visual recovery associated with PRK."

In PRK, Gordon says, the doctor removes the top layer of cells, called the epithelium. "Then you do the lasering and remodeling right on the surface of the cornea. The reason you get a delay in visual recovery and some pain is that removing the epithelial layer is like having a large scratch on the surface of your cornea that has to heal over.

"With LASIK, the surface of the cornea is essentially untouched because you make a little flap in the very upper layer of the cornea, then you do the lasering and reshaping of the cornea underneath the flap," he says. "The flap folds back and conforms to that new shape, so you don't have that scratch that has to heal on the surface of the cornea." Gordon, who is in private practice at the Vision Surgery and Laser Center in San Diego, was one of the surgeons involved in the study.