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 the exact 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.
However factors that may lead to a person requiring glasses or contact lenses after surgery include:
- 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 for each patient to the treatment.
- In individuals with higher levels of refractive error it's harder to hit an exact refractive outcome target. A simple analogy for this is that it's 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).
- Hyperopic patients in general do not achieve 20/20 vision as often as myopic patients. Still, as a refractive surgery technology, LASIK works extremely well in most cases and can help greatly decrease a person's dependence on glasses and contact lenses for most viewing situations.
