Medicine: Shaping Up the Blurry Eye

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 José Barraquer of Bogotá, 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.