Now a neurobiology study at Cornell University suggests that internal parts of the eye indeed can compensate for less-than-perfect conditions in other parts -- either developmentally (during the lifetime of one individual) or genetically (over many generations).
Results of the study, "Internal compensation for corneal astigmatism and high-order aberrations of the eye," were reported to the fourth International Congress of Wavefront Sensing and Aberration-free Refraction Correction, Feb. 14-16 in San Francisco, by Howard C. Howland, Jennifer E. Kelly and Toshifumi Mihashi. Howland is a Cornell professor of neurobiology and behavior and director of the university's Developmental Vision Laboratory; Mihashi is the chief scientist at the research institute of the Tokyo-based Topcon Corp., manufacturer of a wavefront analyzer used in the study; and Kelly is a Cornell senior who used the wavefront analyzer as part of her honors thesis by testing the vision of 20 other undergraduate students.
Wavefront analysis is a recently developed technique for "seeing," with computer-based mathematical simulation, more precisely what the eye perceives. A beam of harmless laser light shines through the eye's optics (the transparent cornea, which begins to focus light, and the lens, which completes the focusing) toward the retina, where millions of photoreceptor cones and rods line the rear surface of the eye.
As the light rays are reflected back through the internal optics and exit the eye, the wavefront analyzer measures and computes deviations from a perfectly formed light beam or test pattern a short distance in front of the eye. Light rays exiting an optically perfect eye should be perfectly parallel, but irregularities in the thickness or shape o
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Contact: Roger Segelken
hrs2@cornell.edu
607-255-9736
Cornell University News Service
17-Feb-2003