M.D. Refractive surgery encompasses a multitude of techniques designed to correct errors of refraction and improve uncorrected visual acuity. Because the shape of the cornea so profoundly affects the refractive state of the eye, most forms of refractive surgery attempt to alter its convex curvature.
Light is focused, or refracted, by the cornea, the clear front window of the eye.
Your vision is clear if the cornea and lens focus the image precisely on the retina, a layer of light sensitive cells that lines the back of the eye. When images are not focused onto the retina, a refractive error exists. The definitions of common refractive errors are listed below. The medical term for nearsightedness. If images are focused in front of the retina, distant objects appear blurry.