Collagen Crosslinking

Corneal crosslinking (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 Crosslinking 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.

Corneal crosslinking is most effective if it can be performed before the cornea has become too irregular in shape or there is significant vision loss from keratoconus or other causes of corneal ectasia. If applied early, CXL typically will stabilize or even improve the shape of the cornea, resulting in better visual acuity and an improved ability to wear contact lenses.

Other potential applications of CXL include the treatment of corneal ulcers that are unresponsive to treatment with topical antibiotics. Studies also have found that corneal cross-linking can be effective for eradicating a variety of corneal infections.

The crosslinking procedure takes 60 to 90 minutes in most cases. If you are receiving epithelial-off crosslinking, your surgeon will place you in a reclining position and remove the epithelial layer from your cornea. Riboflavin eye drops will then be placed.
If you are receiving epithelial-on crosslinking, you are placed in a reclining position, and riboflavin drops are started. After enough time has passed (depending on the technique), the surgeon will evaluate your eye to ensure that the cornea has sufficient riboflavin present.

The corneal thickness will be checked, and then the UV light will be applied for up to 30 minutes.