Kathryn M. Hatch, MD; William B. Trattler, MD


May 16, 2012

In This Article

Corneal Collagen Crosslinking: The Methods

Collagen crosslinking, an investigational treatment in the United States, was first performed in Europe in the late 1990s for the treatment of ectatic corneal conditions. The treatment combines riboflavin and ultraviolet A (UVA) light, allowing the formation of reactive oxygen species, with the goal of halting the progression of corneal disease.[1,2,3,4]

For riboflavin to act as a catalyst in this process, it must first be absorbed into the corneal stroma. Because the corneal epithelium acts as a barrier to riboflavin absorption, it can be removed before treatment with UV light.

The Dresden technique, or "epi-off" crosslinking, is initial removal of the central 9 mm of epithelium, followed by 30 minutes of riboflavin administration. Subsequently, UVA light is applied for 30 minutes, followed by bandage contact lens placement. Epi-off crosslinking can be effective in reducing keratometry readings.[1,3,4,5] The potential risks of this procedure include initial worsening of vision in the first month, pain, haze, corneal melt, and infection.[6]

Dr. Brian Boxer Wachler was the first to perform transepithelial crosslinking, or "epi-on" crosslinking, in 2004. Because the epithelium is not removed, riboflavin loading requires more time than with epi-off techniques. Epi-on crosslinking has several distinct advantages: faster visual recovery; reduced pain; and reduced risks for delayed epithelial healing, infection, and visually significant corneal haze.