Comparison of artificial and accidental laser-induced macular scotomas on human contrast sensitivity

Harry Zwick; James W. Ness; Jerome W. Molchany; Bruce E. Stuck

doi:10.1117/12.237502

1 April 1996 Comparison of artificial and accidental laser-induced macular scotomas on human contrast sensitivity

Harry Zwick, James W. Ness, Jerome W. Molchany, Bruce E. Stuck

Proceedings Volume 2674, Laser-Inflicted Eye Injuries: Epidemiology, Prevention, and Treatment; (1996) https://doi.org/10.1117/12.237502
Event: Photonics West '96, 1996, San Jose, CA, United States

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.

Citation Download Citation

Harry Zwick, James W. Ness, Jerome W. Molchany, and Bruce E. Stuck "Comparison of artificial and accidental laser-induced macular scotomas on human contrast sensitivity", Proc. SPIE 2674, Laser-Inflicted Eye Injuries: Epidemiology, Prevention, and Treatment, (1 April 1996); https://doi.org/10.1117/12.237502

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