Collagen cross-linking is an outpatient surgical procedure which is highly effective in preventing the deterioration of keratoconus. If it is done early enough it can prevent the extreme thinning of the cornea that could otherwise result in scarring and a need for corneal transplantation. It was first developed in Germany in 1998 and has become a critically important treatment for keratoconus.


Keratoconus is a genetic disease of the cornea in which the collagen fibres responsible for the strength of the cornea become progressively weaker resulting in thinning and subsequent ballooning (ectasia) of the corneal surface. The irregular shape caused by the thinning process results in poor vision and requires corneal transplantation surgery in 30% of untreated eyes.


All patients with keratoconus whose corneas are shown to be progressively thinning and losing shape. Keratoconus rarely deteriorates after the age of 35 but there is significant deterioration in one’s teens and early twenties and cross-linking is enormously beneficial at this time.


The procedure entails the saturation of the cornea with riboflavin (vitamin B2) drops followed by the activation of the riboflavin by ultraviolet light. The subsequent reaction which takes place inside the cornea results in strengthening of the collagen fibres which are responsible for the tensile strength of corneal tissue.

Cross-linking is done as an outpatient procedure in the consulting rooms. Drops are used to anaesthetise the cornea and the thin layer of cells on the front of the cornea (epithelium) is carefully removed. Riboflavin drops are applied to the eye every 2 minutes for half an hour and then an ultraviolet light is shone onto the cornea for an additional 30 minutes while more drops are applied. Afterwards a soft contact lens is placed on the cornea which acts like a bandage while the epithelial cells grow back over the next few days.