Radial keratotomy isn't a good idea for a pilot

But in general, it yields 20/20 vision in 60% of patients

Medical Information Service

Q I am a 46-year-old, athletic man and avid private pilot. A year ago I began to be nearsighted and now wear glasses. Could I have radial keratotomy performed on my eyes and get rid of my glasses? And wouldn't this be safer for flying?
A Most near-sighted vision can be corrected with a surgical procedure called radial keratotomy or RK. In recent studies, about 60 percent of RK patients achieve 20/20 vision or better without eyeglasses or contact lenses.
	But the procedure may not be advisable for pilots and air crew members. RK can have unpredictable side effects, including overcorrection, undercorrectioh, a significant fluctuation between day and night vision and an unusual sensitivity to glare. Plus, the effects from high gravity forces on the RK eye are still not understood.
	An article published in the journal Aviation, Space and Environmental Medicine in August 1990 concluded: "Radial keratotomy presently appears to be fraught with intrinsic hazards and is imprudent and inadvisable for pilots or aircrew, in whom long-term stable, nonfluctuating, asymptomatic, keen vision is required in both bright and dim light."
	Radial keratotomy, first introduced in the United States in 1978, is a surgical procedure used to correct nearsighted vision.
	According to a report published in the October 1991 issue of the journal Cornea, RK's success and safety rely on careful case selection, appropriate instrumentation, specialized training, and the ability to perform complex secondary procedures to correct surgical complications.
	Dr. Peter Hersh of the Cornea Service, Harvard Medical School, writes that radial keratotomy is considered safe "when performed with compulsive attention to surgical detail and postoperative follow-up."
	The largest and longest followup study of radial keratotomy patients is the Prospective Evaluation of Radial Keratotomy (PERK) study, begun in 1981. It has followed over 793 eyes receiving a standardized RK surgery by twelve specially trained surgeons at nine centers in the United States.
	The PERK study found that five years after RK surgery, 60 percent had uncorrected vision of 20/20 or better, 88 percent had vision of 20/40 or better, and 2 percent had vision of 20/200 or worse.
	On 12 percent of the eyes, second operations were needed to further correct vision.
	Severe vision-threatening bacterial infections occurred in 2 out of the 793 eyes. Both eyes recovered sufficiently to achieve 20/20 vision with eyeglasses.
	It's difficult to predict the outcome of RK surgery on a patient by patient basis because every one's corneas. respond to surgery and the healing process differently. For instance, one out of five eyes continues to change up to five years following surgery.
	Dr. James Salz, a noted and experienced RK surgeon from the Cedars-Sinai Research Laboratory at the University of Southern California, maintains a conservative approach to RK surgery. Unless they have to meet visual requirements for a job, people who are successful contact lens wearers are encouraged not to have radial keratotomy, Salz wrote in the January issue of Refractive & Corneal Surgery.
	Some of the PERK study investigators are now involved in clinical trials of a new procedure to correct both nearsightedness and farsightedness using excimer lasers to remove the top layers of corneal cells. The FDA hasn't approved the new approach for general use.

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