What Are The Chances Of Regression After LASIK Surgery?

Most LASIK patients do not regress after surgery. After the initial few months, the curvature of the cornea should remain reasonably stable. Mapping the cornea with computerized topography shows that the majority of LASIK patients achieve a stable refraction within the first three months after surgery. People with high myopia, however, may require six months or longer.

Persons who do experience a drop in the effect of the procedure usually were severely myopic before surgery. Doctors do not know why these patients occasionally regress, but we surmise that the problem is related to the depth of the laser ablation and the healing process. The more treatment necessary, the more the stroma or middle layer of the cornea must remodel itself during the first couple of years after surgery. In addition, the epithelium may grow back a little thicker over the lasered area, especially in highly myopic patients. To overcome large amounts of nearsightedness, the laser must make a deeper ablation than to treat mild cases. The deeper the treatment, the more the body tries to fill in the depression, or "divot," with new epithelium. This natural healing response may contribute to slight-to-moderate post-surgical regression in highly myopic patients.

LASIK neither slows nor hastens the normal progression of nearsightedness. Some myopic patients, unfortunately, naturally continue to get a little more nearsighted throughout their life. If the eyeball gets slightly longer or if the crystalline lens starts to develop a cataract, the person will become more myopic even though the corneal curvature is stable. No matter how much near-sightedness naturally progresses with time, patients still should see better without glasses if they have LASIK.

Consider, for example, a thirty-year-old man with -7 diopters of myopia. Over a five-year period, with or without surgery, he may naturally develop another diopter of refractive error. Without any surgery, his correction would now be -8 diopters (severe myopia). But let's say he had LASIK at thirty, and his correction was reduced to -1 diopter (mild myopia). Five years pass. His eyeball naturally elongates so that his refractive error increases to -2 diopters. At this time, he might wish to consider a re-treatment or enhancement procedure.

Scientists have noticed that people who do large volumes of close work tend to be more myopic than people who work outdoors, such as construction workers, who must focus in the distance. As you may know, when you look at a near object, your eyes converge. Pulled inward during years of reading, your eyeball could become slightly longer. An increase of only 1 millimeter in the length of the eyeball will increase myopia by as much as 3 diopters. If you squeeze a tennis ball and quickly let go, it will go back to its original shape. If you squeeze the ball sixteen hours a day for ten years, it is not unreasonable to postulate that the ball's shape could elongate slightly.