After LASIK
Author: Sherman Winston Reeves, M.D., M.P.H.
Is 20/20 vision guaranteed with LASIK?
LASIK surgery is an extremely advanced technology for surgical vision correction. The excimer laser is one of the most precise instruments available for use in modern medicine, and it can be programmed to match exactly the refractive correction your eye needs to see well. As such, the vast majority of people undergoing LASIK surgery are very happy with their post-procedure vision. In fact, a person’s happiness with their vision after the procedure is a far more important measure of success than the somewhat arbitrary “20/20” measurement done in a dark room of a doctor’s office.
Several factors may lead to a person having vision issues after the surgery which still requires additional help from glasses or contact lenses. The excimer laser is precise enough to inscribe letters on a grain of sand and could correct an inert object, such as a piece of plastic, exactly as predicted. However, in LASIK surgery, it is not being applied to something inert, but rather, a living tissue, the cornea. Because of this, and because of the individual healing response of each patient, there is some variability of response in patient to the treatment. Additionally, in individuals with higher levels of refractive error, it is harder to hit an exact refractive outcome target. A simple analogy for this is that it is much easier to make a put in golf (or correct a low amount of vision) than make a hole-in-one driving from the t-box (or precisely correct a very high amount of vision).
Data from the clinical trials of for the currently used excimer lasers supports the assertion that LASIK surgery works very well for most people. For example, for the most recent trials of the VISX S4 laser, the most commonly used excimer laser in the United States, 92% of eyes with low to moderate amounts of mypopia achieved 20/20 or better at 3 months time and 98%. Higher levels myopia and hyperopia may have a somewhat lower chance of 20/20 vision after the procedure. 20/40 vision is the minimum needed in most states to drive without glasses or contacts
