LASIK surgery is a promising but "off-label" procedure.

Off-label doesn't mean illegal. It means the operation is so new that it uses devices originally designed for different operations.It does mean that just possibly not all of the potential complications are understood fully. LASIK is more complex and thus demands more surgical skill than some earlier types of laser surgery.

Dr. Thomas E. Clinch of the University of Utah's Moran Eye Center, who has performed LASIK and the more traditional PRK laser eye surgery, is in a good position to compare the two.

He said the excimer laser used in both surgeries is approved in the United States to make corrections to eyes that are nearsighted up to minus-six diopters.

The microkeratome that cuts the cornea in LASIK is also an approved device for eye surgery.

"However, in the United States the use of LASIK is considered an off-label use of those two pieces of equipment. There has been no completed study of the results of LASIK in the United States. Present studies are under way," he said.

Clinch said studies in foreign countries, where LASIK has been used longer than here, show the procedure has similar results to PRK, "but not better or worse.

"The risk of corneal scarring in the correction of approved amounts of nearsightedness, up to minus-six and minus-seven (diopters) with PRK is very, very low, and much less than 1 percent."

The advantage of LASIK is its faster visual rehabilitation of patients whose vision before correction was minus-five diopters or worse, he said.

With PRK, vision can take one or two months to stabilize, "but it usually only takes several weeks." The patient's vision will change slightly for a year or two after the operation, but most of the healing will take place within the first month, he said.

"With LASIK you have a more rapid visual recovery, within a day or two."

Potential complications that could occur with LASIK include irregular astigmatism, which could develop if an irregularity is left in the corneal surface; loss of the corneal flap that the microkeratome makes, and even an accidental perforation of the eye, Cline added.

"The catastrophic risks with the microkeratome are exceedingly rare. However, a small but not insignificant number of patients can develop a small amount of crinkling or irregularity to their corneal surface."

Long-term results for the older PRK operation are excellent, and Cline expects that the same will be true for LASIK.

"At the present time, I will not quote patients a visual success rate with LASIK because I'm involved with clinical studies that look at the safety and efficacy of the procedure. What I would say is that the patients I have treated with the technique have all done well and are pleased with the techniques."

But approximately 1,000 cases should be studied before ophthalmologists begin quoting statistics, and in this country such studies aren't completed. An ongoing study shows that for moderate to high levels of nearsightedness, PRK and LASIK give similar sharpness of vision at one month, and probably identical levels at six months after the operations.

"I'm pleased and optimistic about my results with LASIK.

"However, I do think it important to tell patients that, at the present time, it's an off-label use, and it is critical for us to obtain more information and results of this technology, before we can outright say it is as safe as doing PRK for low levels of nearsightedness."