August 18, 1999
Web posted at: 11:45 a.m. EDT (1545 GMT)
Whom it helps
RK, or radial keratotomy, is generally used for those
with low to moderate nearsightedness but is rarely done now, surgeons say, because the newer surgeries usually provide better results and quicker healing times.
How it is done
In RK, a surgeon makes a calculated number of incisions in the periphery of the cornea, flattening the central part enough so that light rays will focus on the retina and improve vision. AK, or astigmatic keratotomy, is a similar procedure, meant to correct a cornea's irregular shape and restore clear vision.
In one large RK study, 64 percent of patients did not wear glasses or contacts five years after surgery while 36 percent did, at least some of the time, according to the American Academy of Ophthalmology. AK works best for astigmatism of about 2 diopters, doctors say, and in patients who aren't
nearsighted or farsighted.
What can go wrong
The cornea heals slowly after these surgeries, which
causes some concern. Other complications might include fluctuating vision, infection, a weakened cornea, glare or star bursts around lights.
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