By Derek Prabharasuth, Body1 Staff
Get rid of those glasses and throw away the contact lenses. Approximately 750,000 people this year are expected to undergo laser eye surgery to correct their vision. The procedure uses a laser to reshape the cornea and costs about $4400 for both eyes. Not bad considering this operation is a one time procedure that could improve vision for life.
Nearly one in four people in North America have nearsightedness or myopia, stemming from an abnormally steep cornea curvature. Light entering the eye focuses too far in front of the retina, causing the eye to perceive objects as blurry. In contrast, farsightedness occurs when the cornea’s curvature is too flat, thereby causing the light to focus behind the retina. Again the eye perceives the object as blurry. Eye glasses and contacts have long served to correct vision by helping the eye focus light properly, but many people believe these techniques to be invasive.
Laser eye surgery corrects eyes by first cutting a thin flap in the cornea, then shooting 10-second laser blasts into the opening of the eye, and then finally closing the flap. The entire procedure lasts less then 20 minutes. There are two types: laser-assisted in situ kermatomileusis (LASIK) and photorefractive keratectomy (PRK). In LASIK, the more popular of the two, no flap is created because the laser reshapes the cornea starting from the outer surface and leaves the epithelium of the eye intact. As a result, the cornea generally heals faster. Others believe PFK is the best choice for patients with low prescriptions since a smaller amount of the cornea is excised.
Laser eye surgery is also used to fix farsightedness but yields results generally yield less potent results. In this procedure, surgeons must build up the cornea’s curvature instead of reducing it as in the case to fix near sightedness. Another disadvantage is that laser eye surgery must be performed more than once because collagen around the eye eventually loosens.
Disadvantages of the procedure still remain even with all benefits of laser eye surgery. For instance, physicians suggest that people whose vision has not stabilized should not get laser eye surgery. People with severe myopia are also not considered prime candidates because the surgery would cut too deeply into the cornea.
Eyes of some patients who have undergone laser eye surgery have actually become worse. The best guess is once or twice per 100 operations, though national statistics have not yet been established. Findings during a six-month study by the Food and Drug Administration found that after surgery: 3.5 percent saw halos around lights, 3 percent had worse vision than when they wore glasses, and 1.7 percent suffered from severe glare. Most doctors cannot explain why procedures went awry.
Scientists, however, are currently attempting to perfect measurement accuracy. A company in Orlando has developed a laser machine that uses missile defense technology to monitor the eye and stop the laser within one-4000th of a second, thereby greatly reducing the risk of improper cutting of the eye during surgery. In this technology, a “ladar” is used to detect eye movement while the computer instructs the treatment laser to adjust with the patient’s eye’s movement. A company spokesman claims that people will be able obtain “super vision” by 2001.
References:
www.usatoday.com
Daly, Jim. (2000, August 29). A nation looks for a permanent solution to nearsightedness. The Boston Globe, pp. C1, C4.
