Keratotomy Found Effective but Unpredictable
Two-thirds of those who had eye surgery to correct nearsightedness were able to see without glasses four years later, but doctors still cannot predict the outcome of the costly operation, a study found.
“Our study and others have demonstrated fairly well that there are some adverse outcomes, but they are relatively rare,” said John Carter, coordinator of the study, based at Emory University in Atlanta.
The surgery, known as radial keratotomy, is painless and can be performed on an outpatient basis. It involves making cuts in the cornea in a pattern resembling the spokes of a wheel. The purpose of the procedure, introduced in 1976, is to reduce the cornea’s curvature. It costs about $2,000 per eye, Carter said.
For four years, researchers tracked 390 patients who had undergone the surgery on one eye between March, 1982, and October, 1983. Visual sharpness was improved to better than 20/40 in 76% of eyes, the researchers reported.
Most patients--69%--had visual sharpness of 20/200 or worse before the operation, and none had sharpness better than 20/40, the researchers reported in Friday’s Journal of the American Medical Assn.
But 11 patients who had 20/20 vision or better with corrective lenses before the surgery suffered a significant loss of visual sharpness after the procedure, even with glasses or contact lenses, they reported.
Infections developed in two patients, who were successfully treated with antibiotics and without vision loss, Carter said in a telephone interview Thursday.
Among the 323 patients who had both eyes operated on, 64% said they wore no corrective lenses four years after the surgery, the researchers said.
“It is generally thought to be a safe procedure--and effective--and it does result in the reduction of myopia,” Carter said.
“A major qualifier is (that) no surgeon can tell a patient exactly what his outcome will be,” Carter said. “There’s unpredictability.”
The study did reveal that patients who started with the most visual acuity, or sharpness, before surgery came closest to full restoration of acuity after the operation.
But the unpredictability of the outcome of the procedure remains “unacceptable,” the researchers said.
“I think it’s safe to say that the predictability is better now than it was, but there’s still a range of outcomes,” Carter said.
Dr. Perry S. Binder of UC San Diego cautioned that radial keratotomy “is not intended for all myopic patients just because they wish to see without spectacles or contacts.”
Besides unpredictability and instability of the eye’s effectiveness as a lens after surgery, the tissue being operated on is healthy, making surgeons who do not specialize in the procedure leery of it, Binder said in an editorial in Friday’s Journal.
