ROCHESTER, N.Y, June 14 -- A University of Rochester scientist has developed a system based on adaptive optics that has provided research subjects with an unprecedented quality of eyesight. The work, announced at the summer meeting of the American Astronomical Society in Rochester, dramatically improves the sight even of people who have 20/20 vision. David Williams uses adaptive optics, a technique originally used by astronomers to enhance images from telescopes by correcting for aberrations in the atmosphere. Williams uses the technology by pointing a highly focused spot of light into the eye of a subject and then measuring the reflected light. He then sends the measurements to a deformable mirror that can be shaped according to the size of a person's eye. This technique alters the light in such a way that it exactly counters the specific distortions in a person's eye. Experiments have shown that correcting these imperfections can enhance even normal vision.