Custom Contact Lenses for the Visually Impaired to be Tested

2005-02-08 - Rochester, N.Y., USA: A scientist at the University of Rochester Eye Institute is developing customized contact lenses in a four-year effort to improve the vision of people whose eyesight remains poor even with the best conventional surgical techniques, contact lenses and glasses available.

The research study will include 30 adults who have had a corneal transplant or who have a condition known as keratoconus, an abnormal cone-shaped cornea. Oftentimes such people have blurry vision, and their eyesight often lacks in other ways - they may not able to see well at night, or they may have low contrast.

Such patients typically have to learn to live with their poor vision. Most of their visual problems arise from optical imperfections that weren't even known to exist until a University of Rochester team developed within the last decade a sophisticated system that discovered the abnormalities. The work has as its basis the same technology - adaptive optics - that helps astronomers remove the twinkle from starlight to get accurate images of the heavens.

Geunyoung Yoon, Ph.D., assistant professor of ophthalmology at the University of Rochester Medical Center, is setting out to develop more sophisticated equipment to measure the imperfections in the human eye, in an effort to discover exactly why these patients don't see as well as most people. Scientists know that imperfections that are usually subtle in most patients can be massive in patients who have keratoconus or have had corneal transplants; Yoon will try to specify exactly how the problem might be diagnosed and corrected.

Yoon, who runs the Customized Vision Correction Laboratory at the university's Center for Visual Science, will make sensitive measurements of each participant's eye. Then he'll use a laser to sculpt a soft contact lens for the patient, tailored precisely to counter the patient's unique optical aberrations. Then the patient will try out the custom contact lens, and Yoon will measure the results.

"It's a very complicated project," says Yoon. "A contact lens can move quite a bit on the eye, and that makes it difficult when you're talking about a customized contact lens fitted to correct for the most minute imperfection."

Some of the prototype lenses to be tested in the study will be made by Bausch & Lomb, which collaborates closely with Yoon and other scientists at the eye institute.

Yoon, a native of South Korea, joined the faculty of the Rochester Eye Institute two years ago. He earned his doctorate at Osaka University in Japan, where he worked on fusion experiments with one of the world's largest and most powerful lasers. Then he decided to turn his skills toward biomedical applications and studied physiological optics in the human eye as a researcher with David Williams, director of the university's Center for Visual Science.

Since Williams and colleagues first applied adaptive optics to the human eye, scientists around the world, including those at the Rochester Eye Institute and Bausch & Lomb, have been racing to develop ways to correct previously unknown imperfections and improve eyesight to unprecedented levels. Currently, no company offers commercially available custom contact lenses that correct for such flaws.

Healthy adults with cornea problems who would like more information about the study should call (U.S.)585-273-3084. The project is funded with $700,000 from the U.S. National Eye Institute.