Corneal cross-linking (CXL) is an in-office eye procedure that strengthens the cornea if it’s been weakened by keratoconus or other corneal diseases. Alternative and brand names for the procedure include corneal collagen cross-linking, 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. Corneal cross-linking 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.