Shaping Up the Blurry Eye

By Anastasia Toufexis

A boom in operations to change corneal curvature

Useful as they may be, eyeglasses are widely perceived as a mixed blessing, clumsy, detracting from appearance, a sign of age. Contact lenses are not ideal either: often difficult to manage, uncomfortable to wear, easy to lose. Is there any other option? Some ophthalmologists now think there is. They say two common vision problems--near- and farsightedness (myopia and hyperopia)--can be corrected or eased with surgery that reshapes the cornea, the eye's outer covering.

Light enters the eye in parallel rays, which are gradually bent as they pass through the cornea and lens. In the normal eye, they converge, or focus, precisely on the retina at the back of the eyeball. Electrical impulses then transmit a sharp image to the brain. In the nearsighted, however, the eyeball is usually too long or the cornea too curved, so that the rays come to a focus in front of the retina. In the farsighted, the eyeball is too short or the cornea too flat and the light rays, if they could pass through it, would converge behind the retina.

One way to correct these conditions would be to change the curvature of the cornea so the images fall directly on the retina. The pioneer of surgery that accomplishes that optical feat is Ophthalmologist Jose Barraquer of Bogota, Colombia, who for the past two decades has been performing a variety of delicate and complex corneal operations that he calls refractive keratoplasty (an operation on the cornea for optical reasons). In one procedure known as keratomileusis (cornea carving), the front of the cornea is sliced off with a high-speed vibrating blade, quickly frozen, and then reshaped on its underside by a lathe set by computer calculations. After thawing, the cornea slice is stitched back on the eye. To correct nearsightedness, the surgeon removes tissue from the center of the cornea, thereby flattening it. In farsighted patients, tissue is removed from the periphery to accentuate the curve. A similar operation, called keratophakia (cornea lens), is used to correct only farsightedness. After the front of the cornea is sliced off, a reshaped donor cornea (from an eye bank) is inserted in its place. The front of the original cornea is then sewn back on, resulting in a more sharply curved structure.

These operations take an hour, are done under general or local anesthesia and cost about $3,000. The patient wears an eyepatch for a day or so. After a month the stitches are removed with almost no scarring. In 15 years, Barraquer has done about 4,000 operations with apparently good results. Most people see without glasses almost as well as they did previously with glasses. But the operations are not for everyone. Dr. Casimir Swinger of Manhattan's Beth Israel Medical Center, one of those who has recently brought the procedures to the U.S., says that they should be used mainly for patients with severe refractive errors who cannot tolerate contact lenses. That group includes many who have had cataracts removed.

A still newer and more controversial corneal operation was developed by Soviet Ophthalmologist Svyatoslav Fyodorov. In 1973 he examined a nearsighted 16-year-old youth whose glasses had been smashed in a fight. The shards had cut the cornea of one eye. Three days later the boy could see perfectly out of the eye--without glasses. The injury had inadvertently flattened the cornea.

In the operation that was inspired by the accident, a procedure called radial keratotomy (a cut or slice into the cornea), the surgeon makes 16 or so incisions into the cornea. The cuts, varying in length and depth, extend from the outer edge of the cornea toward the center like spokes of a wheel. The internal eye pressure will stretch the nicked regions, thus flattening the center of the cornea.

Fyodorov and his colleagues have performed more than 2,000 "radial ks" with, they claim, most of the cases improving to at least 20/25 vision. So far, about 2,000 operations (average cost: $1,000) have been done in the U.S., but the procedure, which takes between 15 and 45 minutes and can be performed under local anesthesia, is so simple its popularity is increasing among doctors and patients alike. Some people, like pilots, policemen and firemen, are clamoring for the surgery to pass required visual tests. Others are seeking it for reasons of vanity.

Nonetheless, many ophthalmologists believe the enthusiasm is premature. Aside from Fyodorov's claims, which some Americans find suspect, there is little solid information on long-term benefits or problems. Though limited studies confirm that radial ks improve vision at least temporarily--although not to any great extent--many patients seem to be bothered by glare at night. Also, as much as half of the initial improvement vanishes within three months. Moreover, because the surgeon is cutting through almost nine-tenths of the cornea's thickness, there is the risk of perforation, an injury that could lead to blindness. Declaring that the operation is still experimental, an advisory body to the National Eye Institute has urged doctors to avoid this surgery until its results have been fully evaluated.

--By Anastasia Toufexis.

Reported by Adrianne Jucius/New York

With reporting by Adrianne Jucius/New York

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