Refractive Surgery

The goal of any refractive surgery is to create a cornea which is perfectly round and all light rays are focused on the retina. This is achieved by flattening the myopic cornea, steepening the hyperopic cornea, and/or flattening one axis more than the other in the astigmatic cornea.

Refractive surgery to correct myopia (nearsightedness) includes radial keratectomy (RK), photo-refractive keratectomy (PRK), and laser-assisted in-situ keratomileusis (LASIK). PRK and LASIK are procedures in which the cornea is flattened by a laser.

The advantage of the laser treatments over RK include a more superficial treatment, i.e. the deeper portion of the cornea is left untouched, little or no scarring and less likelihood of complications such as perforation of the cornea. With PRK and LASIK there is a much lower incidence of side effects that were reported frequently with RK, such as glare and night vision problems and should result in a more stable long term outcome as compared to RK. However, low degrees of myopia may be successfully treated with RK.

Overview

Refractive Surgery is a term used to describe procedures that correct a refractive error in the eye. Refractive errors are conditions, which require glasses, or contact lenses to obtain clear vision. They include myopia (nearsightedness), hyperopic (farsightedness) and astigmatism.

Normal Eye

In the normal eye, light rays must be focused directly on the retina to have clear vision.

Myopic (Nearsightedness) Eye

Myopia (nearsightedness) is a condition in which the cornea is too steep, or the eye is too long, as a result, the light rays are focused in front of the retina.

Hyperopic (Farsightedness) Eye

Hyperopia (farsightedness) is a condition in which the cornea is too flat, or the eye is too short, as a result, the light rays are focused behind the retina.

Astigmatic Eye

Astigmatism is a condition in which the eye is not entirely round, but one axis of the Cornea is steeper than the other, so the eye is shaped more like a football than a basketball. This results in the light rays focusing at several different points in relation to the retina.