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Stanford Report, April 24, 2002

Procedure fixes farsightedness with radio frequency energy

By GRACE HAMMERSTROM

The federal Food and Drug Administration has approved a new, laser-less procedure called conductive keratoplasty for the treatment of farsightedness, a condition that affects about 20 percent of the U.S. population. The medical center, where the first half-dozen cases in the United States were performed in a clinical trial, is one of the only places in the country to offer the procedure.

"CK opens up a whole new way of treating patients with hyperopia (farsightedness)," said Edward Manche, MD, assistant professor of ophthalmology and director of cornea and refractive surgery at the School of Medicine. "This non-cutting, laser-less procedure has some real advantages. It's extremely fast -- about three minutes per eye. It puts treatments on the periphery of the cornea, leaving the central portion untouched. And it leaves no scarring in the central part of the cornea."

The procedure may also be better suited for older patients who are more prone to dry eyes, an occasional problem with LASIK, a popular laser eye surgery that corrects vision problems, Manche said.

CK uses a tiny probe, about as thick as a single strand of hair, to send radio frequency energy into the cornea, producing heat that reshapes it. The procedure is an alternative to LASIK, which uses a laser to reshape the cornea, removing tissue in the process. CK is less technically challenging to learn than LASIK and the equipment is less expensive, Manche said.

Manche, who performed the first CK procedure in the United States, has been following patients who have undergone the procedure for the past 2 years. "I noticed the benefits of CK immediately," he said. "My patients experienced consistent visual outcomes throughout the clinical trials." During the trial, no patients lost their best-corrected vision, and almost everyone benefited. "Safety is one of the biggest advantages to this procedure," he said.

For the 20 percent of Americans who are farsighted, nearby objects appear blurry because light rays from those objects focus behind the retina. The condition differs from presbyopia, which also causes difficulty focusing on nearby objects. Presbyopia is an inevitable part of aging, where the lens becomes less elastic and can't focus as easily. By age 50, nearly all people are presbyopic, a condition easily fixed with reading glasses. CK does not treat this common malady.

More than 400 eyes were treated in the FDA clinical trials held at Stanford; the Maloney Vision Institute in Santa Monica, Calif; the Southern Vision Institute in New Orleans; and the New Jersey School of Medicine.

The new procedure does have drawbacks, however. Patients who undergo CK may experience vision fluctuations for several days to several weeks following the procedure. And recovery is not as rapid as it is for LASIK patients, Manche said. The procedure also induced significant astigmatism in approximately 1 percent of patients. In addition, it is not known how long the vision improvements remain in place.

Refractec, Inc. makes the hyperopic radio frequency thermokeratoplasty machine used in the procedure.

For more information about CK, contact Stanford's Eye Laser Center at 498-7020, or visit http://www.med.stanford.edu/school/eye/laser/index.html.



LASIK being tested as treatment for farsightedness
(9/30/98)

Stanford tests experimental treatment for farsightedness (4/14/99)