August 24, 2017

Novel procedure eases vision loss from keratoconus

Uyen Tran, M.D., has performed hundreds of corneal transplants for her patients at Vanderbilt University Medical Center (VUMC).

Uyen Tran, M.D., has performed hundreds of corneal transplants for her patients at Vanderbilt University Medical Center (VUMC).

Uyen Tran, M.D.

Corneal transplants are often the result of three causes: infections, inflammatory diseases and inherited conditions.

One such disorder is keratoconus, an inherited condition that causes a thinning of the cornea and leads to distorted and reduced vision. The cornea, the clear outer lens on the front of the eye, grows weaker causing it to bulge into a cone shape.

In the early stages of the disease, vision problems are often corrected with glasses or soft contact lenses. As it progresses, patients are often moved into rigid, gas-permeable lenses. Advanced keratoconus can require transplantation as the last option to regain functional vision.

But now Tran, associate professor of clinical Ophthalmology and Visual Sciences at the Vanderbilt Eye Institute, is performing a novel procedure with promise to halt vision loss in patients with progressive keratoconus and other corneal degenerations.

Collagen cross-linking, recently approved by the Food and Drug Administration, is an outpatient surgery that uses a liquid form of Vitamin B2 and ultraviolet light to create reinforced mesh to strengthen the cornea.

“This is the first treatment that actually strengthens the cornea,” she said. “It makes the collagen fibrils interlink, flattening out the cornea and decreasing astigmatism.”

The entire procedure is painless and takes less than hour, Tran said.

“I use drops of riboflavin, a form of Vitamin B2, that are administered to the cornea under UV light. The penetration of the compound strengthens the collagen fibrils, forming a sort of mesh, to prevent progressive weakening and in some cases can even reverse some of the disease,” Tran said.

“It can prevent patients from needing a corneal transplant in the future and can allow them to continue to comfortably wear glasses and contact lenses.

“This is not a cure, but as a corneal surgeon, I believe this procedure will significantly decrease the number of transplants.”

Traditionally there has not been a shortage of corneas for transplantation, said Tran, but the increase in LASIK surgeries might change that in the future. LASIK, a popular vision correction surgery, reshapes the cornea for common conditions like nearsightedness, farsightedness and astigmatism.

“We see a condition called post-LASIK estacia or surgical-induced keratoconus,” she said. “Patients experiencing complications from LASIK procedures might be another population seeking treatment with collagen-cross linking. These patients usually experience progressive loss of vision secondary to an increase in irregular astigmatism as the cornea thins.”

The list of patients awaiting the procedure is growing, said Tran, who hopes collagen cross-linking will provide an additional option for her patients and become a first-line treatment in the future.