Keratotomy: success stories and risks


January 24, 1995|By Dr. Genevieve Matanoski | Dr. Genevieve Matanoski,Medical Tribune News Service

In recent years, increasing numbers of people have traded in their eyeglasses or contact lenses for a surgical procedure designed to correct nearsightedness. The surgery, called radial keratotomy, is performed on about 250,000 people a year, generally with good results.

The procedure is not without risk, including blindness in a very small percentage of cases. For a better understanding of the benefits and risks of radial keratotomy, as well as a newer procedure known as photorefractive keratectomy, I consulted Dr. Walter Stark, a professor of ophthalmology at the Johns Hopkins School of Medicine in Baltimore.

Q: What causes nearsightedness?

A: Nearsightedness, or myopia, occurs when light rays are focused by the eye's cornea and lens to a point short of the eye's retina. Glasses or contact lenses correct this focusing "shortfall," so that the rays properly converge at the retina. This differs from farsightedness, or hyperopia, in which rays converge to a point of focus beyond, or in back of, the retina.

Q: How does radial keratotomy work?

A: In radial keratotomy, tiny, spoke-like incisions are made in the cornea. The cuts flatten a misshapen cornea to help bring distance vision closer to what is normal.

Q: What kind of results could I expect?

A: A recently released study by the journal Archives of Ophthalmology confirms that the procedure is reasonably safe and effective. Ten years after surgery, 53 percent of people in the study had 20/20 vision without glasses, while 85 percent had at least 20/40 uncorrected vision, the minimum level allowed to drive without glasses or contacts.

Three percent of people's vision was worse after the surgery.

Q: What risks are involved?

A: It is important to note some other results of the study, which people contemplating the surgery should consider.

Forty-three percent of eyes operated on gradually shifted toward farsightedness: 10 years after surgery, 36 percent were farsighted. The result is that these people may need reading glasses sooner than they otherwise would.

Although farsightedness often is the result of normal aging, complications of the surgery may play a part. Other potential complications include nighttime vision compromised by halos and glare, and in rare cases, blindness.

"Radial keratotomy has certain risk factors involved. Potential patients should stay away from any provider advertising the procedure as completely safe," Dr. Stark said. "The best surgeons are the most conservative, taking the time to explain to their patients all the possible benefits, risks and alternatives, such as continuing to wear glasses or contacts. Only with a full understanding of the surgery can people make an informed, intelligent choice."

Q: How does photorefractive keratectomy differ from radial keratotomy?

A: This newer procedure uses an ultraviolet laser, called an excimer laser, to reshape the cornea for proper light focusing. Although not yet approved by the U.S. Food and Drug Administration, treatment studies over the last seven years showed results comparable to that of radial keratotomy.

Unlike radial keratotomy, which employs cutting, the laser burns off minute quantities of the cornea to flatten it. Some doctors feel this procedure is safer and more precise, and once approved, eventually may replace radial keratotomy. However, similar risks may be related to both types of surgery.

Q: What about cost?

A: Radial keratotomy typically costs $700 to $1,500. Photorefractive keratectomy, once approved, could average $1,500 to $2,000. However, Dr. Stark warns, an infinitely higher price should be considered: the risk of complications and even the loss of sight. For either of these surgeries, caution should be the watchword.

Dr. Matanoski is a physician and epidemiologist at the Johns Hopkins School of Hygiene and Public Health. She is founding director of its Institute for Women's Health Research and Policy.

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