Right now, patients with keratoconus, a degenerative disease of the cornea that affects one in every 2,000 Americans, don’t have very many treatment options. They can get contact lenses to keep up with their declining vision, or eventually, may require a corneal transplant if they become intolerant to contact lens.
“We need to find ways to slow this disease so it doesn’t get to that,” said Stephen Orlin, MD, a cornea specialist and refractive surgeon at the Scheie Eye Institute at the Hospital of the University of Pennsylvania. “And that’s why, after hearing about a procedure that could slow the disease a few years ago, I wanted to bring this new clinical trial to Penn—to help move it closer to a reality for patients.”
Developed over 10 years ago overseas, but not yet approved in the U.S., the procedure works to strengthen the chemical bonds in the cornea with riboflavin (vitamin B2) and ultraviolet light. Over the course of a year in the trial, different intensities of light are applied to the cornea after it has been saturated with the dye for different lengths of time. The idea is to preserve the vision these patients already have and stop the progression of the disease.
Scheie is one of several institutions around the country recruiting patients in the trial that will test the safety and efficacy of the minimally-invasive procedure, known as corneal collagen crosslinking (KXL), for not only keratoconus, but also corneal ectasia, a complication caused by LASIK surgery.
Nine patients have already been enrolled at Scheie.
Keratoconus is a progressive eye disease in which the cornea thins and bulges into a cone-like shape. It is the most common ectatic corneal degeneration in the United States, and its severity ranges. Some lose their vision over time but manage it with corrective contact lenses, while others are worse off, and end up needing a corneal transplant. In that surgical procedure, a damaged or diseased cornea is replaced by donated corneal tissue in its entirety or in part.
It was a clinical study presented back in 2011 at the American Academy of Ophthalmology Meeting that caught Dr. Orlin’s attention. “This study was of particular interest to me because it evaluated a procedure which could hopefully prevent particularly young patients from having progression of their disease to the point where they ultimately might need a corneal transplant,” he said. “That’s a powerful intervention.”
The results of the clinical trial were promising: 30 minutes of dye and then 30 minutes of ultraviolet light was proven to be safe, but also slowed the progression of the disease in patients with keratoconus.
But this new multi-site clinical trial is taking it a step further. Instead of a 30 minute exposure of UV light, the trial is testing out higher amounts of light energy over shorter periods of time, as a way to make it more manageable for patients.
Subjects are randomized to one of three treatment groups. Up to 2,000 study eyes with keratoconus and up to 2,000 study eyes with corneal ectasia after refractive surgery will be randomized. Three doses of irradiation will be tested, with the highest intensity paired with the shortest amount of time (2 minutes and 40 seconds) and the lowest intensity paired with longest amount of time (8 minutes).
Results from the study are expected later next year.
“This study is critically important because, up until now, there have been no pharmacological or surgical interventions to halt the progression of keratoconus or LASIK induced corneal ectasia,” said Dr. Orlin. “There are some other less successful ways of getting contact lens intolerant patients comfortable with their lenses, but this has very limited potential. Therefore, it would be enormously advantageous to prevent this disease from progressing so that we can preclude the need for corneal transplantation in these patients and preserve their vision.”