Corneal cross-linking (CXL) is an in-office eye procedure that strengthens the cornea if it’s been weakened by keratoconus, other corneal disease, or (rarely) a complication of LASIK surgery. Alternative and brand names for the procedure include corneal crosslinking, corneal collagen crosslinking, C3-R, CCL and KXL.
The minimally invasive CXL procedure involves applying liquid riboflavin (vitamin B2) to the surface of the eye, followed by treatment with a controlled application of ultraviolet light, to eliminate corneal ectasia.
The two basic types of corneal cross-linking are:
Epithelium-off CXL. In this type of cross-linking procedure, the thin outer layer (epithelium) of the cornea is removed to allow the liquid riboflavin to more easily penetrate the corneal tissue.
Epithelium-on CXL. In this procedure (also called transepithelial CXL), the protective corneal epithelium is left intact, requiring a longer riboflavin “loading” time.
Corneal crosslinking also can be combined with other procedures for keratoconus treatment. For example, combining CXL with implanting tiny arc-shaped corneal inserts called Intacs has been shown to help reshape and stabilize the cornea in more advanced cases of keratoconus.