Custom-designed contact lenses improve vision in keratoconus patients

Keratoconic patients may be able to avoid surgical treatments for the disease with the help of custom-designed soft contact lenses, according to a press release.

Geunyoung Yoon, PhD, and colleagues at the University of Rochester tested the lenses on three keratoconic patients to determine the quality of visual acuity.

"These people have problems so severe, they can't tolerate glasses. They can't take laser vision correction because they have a very thin cornea around the apex, so it's not an option," Dr. Yoon said. "The only available treatment is to wear hard contact lenses or corneal transplant with a donored cornea if the disease is severe. And with the corneal transplant there is a rejection rate."

The researchers tested a number of lens designs on the subjects' eyes for high-contrast and low-contrast visual acuity, according to the press release. They compared the vision with the custom-designed lenses to vision with conventional lenses and rigid gas permeable lenses.

According to the results, the custom-designed lenses garnered an average improvement of 2.1 lines of visual acuity over the use of conventional defocus and astigmatism corrections alone.

The custom-designed lenses feature irregular front surface profiles designed to correct for specific aberrations of the cornea and crystalline lens, according to the press release. The front profiles were designed by using wavefront sensors to measure how light enters the subjects' eyes through the conical cornea. The front surface of the lens was then sculpted in collaboration with Bausch & Lomb using an oscillating tool lathe.