Keratoconus, a progressive thinning of the cornea the tough transparent curved structure responsible for focusing 75% of the light entering the eye onto the retina is the most common corneal dystrophy in the United States, affecting one in every 1,000 or 250,000 people across all races. It typically begins during teen years and progresses at varying rates until stabilizing usually by age 45.
As the central and inferior areas of the cornea thin and gradually bulge outward, a cone-like shape is formed. This abnormal curvature changes the cornea’s refractive properties causing varying degrees of blurred vision and distortion of objects. Occasional swelling may occur which can, in time, lead to sight-impairing cornea scarring.
Similar cornea distortion and irregularity can also be seen in certain eyes that had Radial Keratotomy, LASIK induced ectasia or trauma.