Adaptive Optics Exposes Visual Defects

ROCHESTER, N.Y., June 14 -- Adaptive optics, originally developed to help astronomers see more clearly through the Earth's atmosphere, has enabled researchers at the University of Rochester to discover that as many as a third of the light-detecting "cones" in a colorblind person’s eye can be missing -- yet amazingly, visual acuity appears unaffected. The work is published in a recent issue of the Proceedings of the National Academy of Sciences.

The findings were possible thanks to a laser-based system developed by David Williams, director of the University of Rochester's Center for Visual Science, and colleagues over the last decade that maps out the topography of the inner eye in exquisite detail. The team built on technology known as adaptive optics, initially proposed by astronomer H. W. Babcock in 1953, then developed by the US military to clear up images from spy satellites. The idea is to correct for aberrations in the atmosphere so that rays of light travel in parallel lines and converge at a single point, delivering a sharp image. Astronomers use the technique in telescopes to grab ever-better photos of the heavens. Williams leads the effort to apply the same technology to human vision.

Joseph Carroll, a postdoctoral fellow at the Center for Visual Science and lead author of the paper, said, "The real lesson learned here is that adaptive optics becomes incredibly powerful when coupled with other technologies. When we combine it with retinal densitometry, for instance, we can determine the amount and kind of pigment in the retina at the cellular level. Our ability to understand the retina and diseases of the retina is going to see big advances as this technology is merged with others."

Noting how useful adaptive optics can be in helping to spot and diagnose disease of the retina earlier than is possible with current clinical techniques, the researchers are working to build five new adaptive optics machines to be used around the world in vision clinics. The cost of the deformable mirror itself -- the "heart" of an adaptive optics system -- is the main stumbling block. At more than $100,000, it is prohibitively expensive, but Carroll and others at the Center for Adaptive Optics, which includes 11 institutions across the country, are working with industry partners to bring that cost to below $10,000.

"Joe Carroll’s research on colorblindness represents a terrific example of cross disciplinary research," said Donald T. Miller, associate professor of Optometry at Indiana University. "The project highlights the significant resolution advantage of adaptive optics technology and demonstrates the enormous potential this technology has for addressing unanswered clinical and scientific questions about human vision."

"This research is really an indicator of how powerful adaptive optics can be," said Carroll. "With it, we’ll be able to understand how our vision works in far more detail, and help to quickly diagnose and treat disease more effectively."

For more information, visit: www.cvs.rochester.edu