Ophthalmology: Linking to the Future of Keratoconus

By Andrew Myers

In a small operating room at Wilmer, eye surgeon Uri Soiberman delicately peels back the outermost layer of a patient’s cornea and applies a few drops of a translucent fluid into the exposed area. Carefully replacing the corneal layer, he then shines ultraviolet light on the area. The whole operation takes less than 90 minutes. 

Known as corneal cross-linking, this relatively simple surgery, which became available at Wilmer in late 2016, is cause for celebration for the sufferers of keratoconus, which occurs in about one in every 2,000 people. 

“Until recently, no drugs or other treatments were available for keratoconus,” says Soiberman. “Patients would often progress to the point where we could no longer correct their vision, and then transplant was the only option to restore vision. But corneal cross-linking gives us a new tool.”

With keratoconus, the cornea grows thin and weak, causing it to bulge into a conelike shape. The result is blurriness and double vision that cannot always be corrected with glasses. Keratoconus begins in childhood and, depending upon the severity, grows worse over time. Some patients will have to undergo a corneal transplant in order to regain functional vision. 

Corneal cross-linking was developed and evaluated by German scientists about 15 years ago and has been thoroughly tested in humans over the last decade. Only recently, however, has the U.S. Food and Drug Administration approved it for use in patients in the United States. Soon after, Wilmer was one of the first eye institutes in the United States to get a cross-linking system. The system facilitates the delicate surgery by administering a controlled dose of ultraviolet light.

With cross-linking, once the surgeon has peeled off the cornea’s outermost layer, or epithelium, he or she applies a series of drops that contain riboflavin—better known as a form of vitamin B2. When exposed to ultraviolet light, riboflavin leads to the production of high-energy molecules that then cross-link the natural collagen fibers in the cornea. The result is a reinforced mesh that strengthens the weak cornea. 

“It is surgery, so it needs to be taken seriously,” Soiberman says, “but it’s quite painless and takes just an hour and a half or so. We’ve had quite a few cases, and they’re all looking very good.”

Cross-linking is not a cure, Soiberman warns. It is more of a maintenance therapy designed to prevent further progression of keratoconus. But for the one in five keratoconus patients whose disease is progressing rapidly, cross-linking can mean the difference between a full-scale cornea transplant and a relatively simple outpatient procedure.