Corneal Cross-Linking Corneal cross-linking using Avedra’s Photrexa products and KXL System is a medical procedure that combines the use of ultra-violet (UV) light and riboflavin (vitamin B2) eye drops. The procedure works by creating new corneal collagen cross-links, which results in a shortening and thickening of collagen fibrils which leads to the stiffening of the cornea. Cross-linking, which has been performed in Europe since 2003, is considered the standard of care around the world for keratoconus. It is used for patients with an eye condition called keratoconus (KC). Where typically a person’s cornea is round and dome-shaped, a patient with keratoconus has a cornea that has become thin and weak causing the development of a cone-like bulge shape. This produces optical irregularities that affect one’s vision. The following WK Eye Institute doctors offer this procedure: Christopher L. Shelby, M.D. Ophthalmologist North, Pierremont Wyche T. Coleman, III, M.D. Ophthalmologist South