Laser surgery can reduce or eliminate your need for glasses or contact lenses by reshaping your cornea, the transparent outer layer that fits over your iris and pupil. Surgeons in Europe began photorefractive keratectomy, or PRK, in the mid-80s. The Food and Drug Administration approved this technique for the treatment of nearsightedness (myopia) and astigmatism in 1995 and of farsightedness (hyperopia) in 1998. A newer technique, another mouthful called laser assisted in-situ keratomileusis, or LASIK, is an increasingly popular alternative to PRK as it boasts a faster recovery period. The U.S. Food and Drug Administration (FDA) has approved over a dozen lasers for use in LASIK since 1998. If your vision is mildly to moderately bad, both techniques promise you about a 75 percent chance of 20/20 vision and a 95 percent chance of 20/40 vision or better, which would make it legal for you to drive without corrective lenses.

Still, you should be aware that even if you achieve 20/20 vision with LASIK surgery, you may not see quite as clearly as you did with your glasses or contacts. The Eye Surgery Education Council, a professional organization of ophthalmologists, says that often your eyesight will not be quite as crisp -- what is called "loss of contrast sensitivity." People who do fine detail work, like architects, draftsmen and others, may want to keep this in mind before deciding whether to have laser surgery.

During PRK, the surgeon painlessly scrapes away the outer layer of your cornea (the epithelium) and then sculpts the underlying tissue with a laser. LASIK involves cutting a flap into the epithelium and folding it back, so that the laser can penetrate farther into the cornea if necessary. Both procedures are good for mild to moderate vision problems, but LASIK can be used to treat more severe myopia as well. And since a clean incision will heal more easily than a scraped cornea, LASIK patients feel less pain, take less time to recover after surgery, and run less risk of scarring that can create a film on the eye's surface. Making a proper incision requires more skill than scraping away surface cells, though, so there's a greater chance of complications from LASIK.

Your doctor will examine each eye and make a map of its surface. Then he or she will calculate how much tissue should be removed in what pattern, and will enter that information into the computer that controls the laser. Anesthetic drops will numb the nerve endings in your eyes. With your eyelids held open by small clamps, you'll actually be able to see what the surgeon is doing. Older machines require you to stare at a red dot in order to keep your eye still. (If your eye wanders, the doctor must take his or her foot off the pedal that operates the laser). But some surgeons now use a suction device to hold your eye steady, and some newer lasers can actually track and compensate for any involuntary eye movement you make. The sculpting takes only a few minutes at most. After PRK you'll need to wear protective contact lenses for a few days while your epithelium grows back; it will be about a week before your eyes are functioning properly. If you've had LASIK, you should be able to see normally within a few hours, but your doctor may ask you to keep your eyes bandaged overnight to be sure that the epithelium re-adheres properly to the cornea.

After either procedure, you may notice some discomfort and sensitivity to light for a few days. Be careful to follow your doctor's directions, and use any eyedrops you're given. If you had PRK, the drops may serve to slow down your healing and lessen your risk of developing a hazy film in your corneas, which can require further surgery to correct. During the first six months after either procedure, your vision may occasionally regress, and you may see halos or starbursts around lights when driving at night.

Serious complications are relatively rare, but the worse your vision is to begin with, the less likely you are to end up with perfect eyesight after surgery and the more likely you are to have side effects. Overall, there's about a 15 percent chance that you'll need follow-up surgery to achieve 20/40 vision. Some surgeons guarantee their work by offering the second surgery for free. About five percent of nearsighted PRK patients end up farsighted and in need of reading glasses because their corneas flatten out too much. LASIK patients face about a one percent chance that the epithelium flap won't heal properly and further surgery will be required. Physician error has left an unlucky few patients with eye injuries that made corneal transplants necessary. European studies have found no long-term problems with PRK. Because LASIK is still so new, there's less safety information available for it. Some patients, however, have developed debilitating visual symptoms like glare and halos that affect nighttime vision.

Ideally, you should be between 20 and 50 years old. Younger eyes are still maturing and changing shape; older ones are likelier to have developed age-related conditions such as glaucoma or macular degeneration. People with mild myopia or hyperopia get the best results. In 2007 the FDA approved the first LASIK device to treat presbyopia, the age-related loss of ability to focus on near objects. The device corrects all nearsightedness in one eye and only part of the nearsightedness in the other eye, so you can rely on one eye for distance viewing and one eye for seeing close-up.

You're not a good candidate for laser surgery if you have eye disease or any immune-system problems like lupus or rheumatoid arthritis, which can interfere with the cornea's healing. Diabetics are also out of the running because their vision can fluctuate with their blood glucose levels. And put this surgery off if you're pregnant, since the shape of your corneas can change while you're carrying a child.

PRK currently costs $2,250 per eye, LASIK between $1,800 and $2,750. Insurers generally don't cover the surgery, because it's not considered medically necessary. The costs may go down soon because of increasing competition as more lasers are approved and more surgeons offer the service.

About one in five ophthalmologists performs laser surgery. Training involves 10 to 12 successful procedures supervised by a surgeon who has mastered the technique. Obviously, the more experienced your doctor is, the better chance you have of getting good results, so ask how many times he or she has performed the operation. Also ask for the percentage of patients who have achieved 20/40 vision or better and the percentage who end up needing a second procedure.

Further Resources

American Academy of Opthalmology

P.O. Box 7424

San Francisco, CA 94120

Phone: (415) 561-8500

http://www.aao.org

U.S. Food and Drug Administration

Lasik Eye Surgery Page

http://www.fda.gov/cdrh/LASIK

References

First published January 2, 1999
Last updated February 14, 2008
Copyright © 1999 Consumer Health Interactive

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