Keratoconus is a disorder that occurs when the cornea, which is typically rounded, becomes cone-shaped. The progression is usually slow and can stop at any stage from mild to severe. This distortion increases as the cornea bulges and thins. The apex of the cornea often scars, reducing the vision. Treatment of Keratoconus is most effective with gas permeable contact lenses, designed specifically for the irregular corneal surface. If contact lens treatment is not successful, a surgical corneal transplant may be necessary.