What Is Corneal Cross-Linking For Keratoconus?
In CXL, a solution of riboflavin (a type of vitamin B) is applied to the cornea and then the front surface of the eye is exposed to a controlled amount of ultraviolet (UV) light. The UV activates a process whereby the riboflavin creates additional bonds between connective tissue fibers made of collagen within the cornea. These "cross-linkings" provide additional strength and rigidity to the cornea.
There are two types of corneal cross-linking, depending on whether the outer layer of the cornea (the epithelium) is left intact or removed prior to the application of riboflavin solution. In "epi-on" CXL, the epithelium is left intact; in "epi-off" CXL the epithelium is removed.
Corneal cross-linking also is used to stabilize the cornea in cases of a rare complication of LASIK surgery called corneal ectasia, which produces similar signs and symptoms as those of keratoconus.
About the Author: Gary Heiting, OD, is senior editor of AllAboutVision.com. Dr. Heiting has more than 25 years of experience as an eye care provider, health educator and consultant to the eyewear industry. His special interests include contact lenses, nutrition and preventive vision care.
Page updated February 2018