Collagen Crosslinking with Riboflavin
Another technique that is being developed for the treatment of keratoconus is that of corneal collagen crosslinking with riboflavin (vitamin B2). This is a 30 minute office procedure during which riboflavin drops are applied to the cornea and then activated by ultraviolet light to "crosslink" or strengthen the structural corneal collagen proteins which are weakened in keratoconus. In studies published so far, this appears to be a simple, effective and relatively inexpensive technique to arrest the progression of keratoconus. Some studies have even found that C3-R can reverse some of the changes of keratoconus resulting in improved visual function. It is possible that this technique can be used in combination with other procedures such as INTACS or PRK. Thus far, studies seem to indicate that this is a safe technique in the short term.
This procedure was introduced in Europe in 2003 and is presently available there and in other parts of the world. It is currently being studied extensively here in the United States under a number of FDA approved protocols. In the published studies, the two noteworthy changes brought about by corneal crosslinking are the slowing and prevention of disease progression and a reduction in corneal curvature (steepness). It is hoped that by treating keratoconus patients early in the course of the disease, stabilization of the corneal shape and contour will occur and progression to the point where a corneal transplant is required will occur less frequently.
Refinements in the procedure are being studied and include a reduction in the treatment time by modifying the ultraviolet exposure (the overall treatment energy is the same), application of the riboflavin without removal of the corneal surface layer (the epithelium), and combining crosslinking with intracorneal rings (INTACS) or photorefractive keratectomy (PRK).
Michigan Cornea Consultants was recently selected as one of the research centers for participation in a United States corneal crosslinking trial looking at a reduction in the treatment time (from the typical 30 minutes of UV exposure to as little as 3 minutes). This study, sponsored by ACOS, has received both Food and Drug Administration (FDA) and Institutional Review Board (IRB) approval. The study is assessing the effectiveness of corneal crosslinking in preventing disease progression and reducing corneal curvature (steepness) in patients with certain forms of keratoconus and post-refractive surgery corneal thinning (ectasia). (see: Patient Services – Research Programs – Corneal Crosslinking . . . for more information on this study)