Eye Surgery Helps Some See Better : Part 3

by Food and Drug Administration (FDA)

(Page 3 of 3)

RK vs. PRK

Jeffrey Robin, M.D., has a unique perspective on RK and PRK. Head of the department of refractive surgery at the Cleveland Clinic, Robin has done both procedures on patients in clinical trials and has, himself, undergone both procedures.

"I've worn glasses since I was eight, and started wearing contact lenses when I was 17 or 18," Robin says. "I went through many pairs of lenses — tore them, slept in them. I was not a good contact lens patient and I detested wearing my glasses, basically because I didn't perceive I was seeing well with them," he says.

About five years ago, at age 35, Robin had an 8-incisional RK in his right eye. A year later, he had PRK in the left. He felt only minor, temporary discomfort after both surgeries, but says that before anti-inflammatory drops were used with PRK, that procedure often produced intense post-surgery pain.

"With RK, vision is almost instantaneously improved — I went from about 20/800 to better than 20/20 the morning after surgery," Robin says. "After PRK, I had better than 20/20 after about 10 days to two weeks. The big difference with the laser is that the correction is solid — there's no visual fluctuations and really no starbursting like you get with RK. Except for the couple of weeks after my RK when I used night driving glasses, I haven't worn glasses since. I've almost forgotten I ever wore them."

Four years of follow-up with PRK has shown fewer complications, such as infection or cataract, than are seen with RK. Also, hyperopic shift has not been seen with PRK, nor is the cornea weakened as it is in RK. On the other hand, Robin says, "we have 15 or 16 years of experience with RK as opposed to about four years with PRK. Between 1 million and 2 million Americans have had RK and probably only 4,000 to 5,000 have had PRK, so we kind of know the warts — the good and bad sides — of RK whereas we don't really know all those things with our more limited experience with PRK."

Both refractive surgeries are considered cosmetic procedures and generally are not covered by insurance. Robin says that RK generally varies from $600 to $1,500 per eye and laser surgery costs around $2,000 per eye.

Prospects for 20/20 in 2020

Visions of a world entirely without glasses in the foreseeable future are probably premature; refractive surgery is not for everyone. "From a medical standpoint, we are most concerned about people who have wound healing problems," Robin says, "because in all these procedures, the results are ultimately affected by two things — what we do as surgeons, and then how the patient's body reacts to the laser or knife wounds."

The procedures should not be done on patients with connective tissue diseases such as rheumatoid arthritis or lupus erythematosus, or on people with uncontrolled diabetes, autoimmune disease, or some eye diseases such as poorly controlled glaucoma, macular disease, retinal problems, extremely dry eyes, and certain corneal problems.

Pregnant women also should not have refractive surgery, because the refraction of the eye changes during pregnancy.

Robin, Hersh and Knight all agree that people who are not comfortable with the possibility that they may still need glasses or contact lenses at least part-time after surgery are probably not good candidates. Prospective patients should carefully weigh their hoped-for benefits against the calculated risks. After all, no surgeon can guarantee 20/20 vision except for hindsightedness.

New Progress with an Old Idea

Refractive surgery is not a new idea. Little wonder, since about one-fourth of the world's population is nearsighted — about 63 million in the United States alone. According to a report in the October 1994 Archives of Ophthalmology on the results of a 10-year study on radial keratotomy, the procedure was first described by European ophthalmologists in the late 1800s. It was further developed in Japan in the 1940s and 1950s, evolved into its modern form in Russia in the 1960s and 1970s, and was first done in the United States in 1978.

Despite RK's long history, refractive surgery is still in its "early toddlerhood," says Jeffrey Robin, M.D. Head of the department of refractive surgery at the Cleveland Clinic, Robin foresees a broader spectrum of procedures, pending laser approval, that will include RK, PRK, and others now under study.

"There's a growing menu of approaches that can potentially help people with a variety of refractive errors — low, moderate and high nearsightedness, farsightedness, and even presbyopia [farsightedness associated with aging]," he says, noting that surgeons are also combining the knife and laser techniques to try to achieve better accuracy and effectiveness, especially for very nearsighted people.

For example, in an experimental procedure called laser in situ keratomileusis (LASIK), the surgeon uses a knife to cut a flap of corneal tissue, lases targeted cells beneath it, and then replaces the flap.

"Possible advantages of LASIK are better results with high myopia, less chance of scarring and haze, faster recovery, and less pain than simple PRK," says FDA's Emma Knight, M.D., an ophthalmologist with the agency's Center for Devices and Radiological Health. "From FDA's standpoint, we want to know not just if LASIK is a good enough procedure, but if it is as good or better than PRK. So we've asked people to do randomized studies. We must also be sure there are not any greater risks than with standard PRK."

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.