HOW WELL DO THESE PROCEDURES WORK?
An easy question, but a complicated answer-mainly because most of these procedures are still too new and still evolving. The largest follow-up studies to monitor the results of refractive surgery have been done on patients who have received RK. One reason for this is simply the comparative volume of patients. Before 1995, RK was the refractive surgery of choice (actually, it was the only approved refractive surgery in the United States). The laser techniques have been “under investigation,” and have been done on limited numbers of patients in research centers, but they were not widely available until 1995. PRK was approved by the Food and Drug Administration only in 1996. Therefore, the total number of patients undergoing laser procedures is still small when compared word the many patients in this country who have had RK.
What’s Considered Effective?
A successful result for most studies is incorrect end vision of 20/40 or better. This is minimal level of vision required by most states in granting a driver’s license without a restriction for glasses or contact lenses. So basically, with 20/40 vision you could see well enough to drive a car. However, for most of us, seeing at a level less than 20/20 is not ideal; we don’t feel that our vision is as clear as it should be. And many RK patients, even those with considered to be “successful,” still need glasses at Lear part-time. (Most of these people, however, feel that this is less of a compromise than wearing glasses full-time.)
The most widely publicized study in refractive surgery so far is the PERK (Prospective Evaluation of Radial Keratotomy) study, sponsored by the National Eye Institute at the National Institutes of Health; it was started in the late 1970’s an has been updates as surgical techniques have changed. Because it’s been around the longest, the PERK study’s findings give a better sense if what happens to an RK patient’s vision over time. The most recent findings show that results of RK surgeries are still very dependent on the amount of myopia that someone has before surgery. The more myopia, the less likely for incorrect end vision after surgery to be better than 20/40. For patients with mild myopia, 92 percent maintained 20/40 vision or better at five years after the surgery. For those with moderate myopia, the number drops to 86 percent, and for those with high myopia, 72 percent had 20/40 vision or better. And 64 percent of all RK patients with any degree of myopia wore neither glasses not contacts give years after surgery. Some people with RK required eyeglass prescriptions because their corneas continued to flatten after the surgery and they became much more farsighted over time.
Early studies on the laser procedures show slightly better results. However, the patients these studies represent-those who enrolled in the research programs-were carefully careened to meet certain criteria, so they may not be representative of the general population; therefore, the results may be slightly skewed.
If you’ve experienced a sudden massive loss of vision it may be glaucoma related. In which case you’ll need an eye doctor that specializes in glaucoma, especially an eye doctor who is experienced in performing trabeculectomies.