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Proceedings Paper

Comparison of artificial and accidental laser-induced macular scotomas on human contrast sensitivity
Author(s): Harry Zwick; James W. Ness; Jerome W. Molchany; Bruce E. Stuck
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Paper Abstract

The effects of human laser eye damage may be modeled by stabilizing a small portion of the visual field on the retina. We compared the effects of such artificial scotomas with accidental human laser induced retinal damage on contrast and recognition sensitivity. Horizontal and vertical output voltages from a purkinje eye-tracker controlled video generated scotomas. Contrast sensitivity functions were obtained with focal acuity targets ranging in spatial frequency from 0.5 to 20 cycles/degree. Target vehicular recognition functions were obtained for larger targets and restricted size range. Artificial scotoma effects demonstrated uniform loss in contrast sensitivity in the presence of central scotomas; paracentral scotomas had minimal effects beyond 10 cycles/degree but were effective from 0.5 to 10 cycles/degree. Similar results were obtained for vehicular recognition sensitivity functions. On the other hand, patient macular injuries resulted in greater suppression of the contrast sensitivity function regardless of whether injury was foveal or parafoveal. Secondary laser induced damage such as scar formation, traction or retinal nerve fiber layer injury may mediate high spatial frequency as well as low spatial frequency loss. The uniform suppression of contrast sensitivity may involve selection of a superior retinal site with an ocular motor component to fine tune the search for remaining `islands' of high photoreceptor density. Such high density photoreceptor patches may serve as a pseudo fovea, if laser induced secondary damage effects are minimal.

Paper Details

Date Published: 1 April 1996
PDF: 8 pages
Proc. SPIE 2674, Laser-Inflicted Eye Injuries: Epidemiology, Prevention, and Treatment, (1 April 1996); doi: 10.1117/12.237502
Show Author Affiliations
Harry Zwick, Walter Reed Army Institute of Research (United States)
James W. Ness, Walter Reed Army Institute of Research (United States)
Jerome W. Molchany, Walter Reed Army Institute of Research (United States)
Bruce E. Stuck, Walter Reed Army Institute of Research (United States)

Published in SPIE Proceedings Vol. 2674:
Laser-Inflicted Eye Injuries: Epidemiology, Prevention, and Treatment
Bruce E. Stuck; Michael Belkin M.D., Editor(s)

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