CONDITIONS & DEFINITIONS
RK and AK
The cornea and lens combine to focus visual images on the back of the eye. When the overall shape of the eye is incorrect or when the curvature of the cornea is incorrect, the visual images are distorted and not in focus. The cornea accounts for approximately 2/3rds of the focusing power of the eye. By surgically changing the corneal curvature, most or all of the blurriness can be overcome.
Radial Keratotomy (RK) is a surgical procedure that can help people with mild to moderate myopia. The technique has been in existence for more than thirty years. During RK, tiny spoke-like incisions are made in a "radial" pattern around the cornea. These cuts in the cornea serve to change the corneal curvature. To correct for nearsightedness, the cuts are used to flatten the cornea.
As with laser vision correction, the vast majority of patients have had their vision corrected to 20/40 or better. It is most effective when treating low to moderate levels of nearsightedness.
Astigmatic Keratotomy (AK) is used to help people with astigmatism. Astigmatism is an uneven curvature of the cornea. It is curved more in one direction than the other, causing a distortion in vision. During AK, one or more surgical incisions are made in the cornea. These incisions help eliminate the uneven curvature and "round out" the cornea. A rounder cornea means objects no longer appear blurred or distorted. AK is sometimes performed at the time of cataract surgery, in order to reduce or eliminate the patient's pre-existing astigmatism.