New system for improving eyesight

17 Jun 2002

Adapting technology originally developed by astronomers to obtain better images of the heavens, a University of Rochester scientist has developed an optical system that has given research subjects an unprecedented quality of eyesight. The research dramatically improves the sight even of people who have 20/20 vision. Vision scientist David Williams presented his work this week at the summer meeting of the American Astronomical Society in Rochester, N.Y.

While the work is still in a research stage, eye-care giant Bausch & Lomb has licensed the technology and is working with University researchers to commercialize it.

"In the old days," says Scott MacRae, one of the world's leading cornea specialists, "we were just trying to correct people's vision problems and treat disease. This new research takes what we consider normal vision and enhances it.

Williams uses technology known as adaptive optics, which was originally developed by astronomers to sharpen images from telescopes by correcting for aberrations in the atmosphere. His researchers direct a harmless, highly focused spot of light into the eye of a research subject and measure the light that is reflected outward. That light provides a glimpse or snapshot of the topography of the eye in exquisite detail. The light is broken up into 217 laser beams that are sent into a sophisticated device known as a wavefront sensor. The sensor analyzes deviations in each beam's path, revealing tiny imperfections or aberrations that exist in the person's cornea and lens.

These precise measurements are sent to a sensitive "deformable" mirror - a mirror that can bend and customize its shape according to the measurements of a person's eye. Such flexible mirrors form the heart of traditional adaptive-optics systems used in astronomy. The mirror in Williams' laboratory is a two-inch-wide device that bends as little as one or two micrometers (just one-fiftieth the width of a human hair) thanks to 37 tiny computer-controlled pistons. This subtle shaping, done in response to the customized measurements of a person's optical system, alters the light in such a way that it exactly counters the specific distortions in a person's eye.

"When you look through an adaptive optics device, the world looks crisper," Williams says. "In some people, the ability to pick up contrast, such as minute patterns of stripes, is increased by a factor of six. It allows for a level of vision correction that's just not available today.

"It's like needing glasses and getting them for the first time. Everything suddenly looks sharper and clearer, no matter how good your eyes are normally. When you're using the adaptive optics system, you just say 'wow.' "

Story courtesy of Opto & Laser Europe Magazine.