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Proceedings Paper

Effect of source intensity on the variability of eye movements during deliberate fixation
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Paper Abstract

During long-term viewing of a continuous light source, head and eye movements affect the distribution of energy deposited in the retina. Previous studies by this group of eye movements during a fixation task were used in revising the safety limits for long term viewing ofsuch sources. These studies have been continued to determine the effect of source brightness on the nature of fixational eye movements VoIuntees fixated for up to 50 seconds on a HeNe laser (? 632 8 nm) masked by a 25 xm diameter aperture to produce a small source subtending OO3 mrad in the visual field. The source was attenuated to yield cornea! irradiance values m the range 0 6 pW/cm2 to 6 tW/cm2 Eye movements were recorded using a Dual Purkmje Image Eye Tracker The hypothesis was that eye movements become more erratic as source intensity is increased toward levels that induce an aversion response This would add a safety maigin when viewing a bright source, as the energy deposited in the retina would be spread over a larger area However, the data do not exhibit any change in the tightness of fixation with increasing source intensity. The area covered by the eye movements during successive 250 ms time slices exhibits a relatively flat trend during the course ofthe 50 second fixation task for all source intensities considered in this study, suggesting that there was no loss of ability to fixate nor drive to an aversion response during the course ofthe trials.

Paper Details

Date Published: 17 May 2001
PDF: 9 pages
Proc. SPIE 4246, Laser and Noncoherent Light Ocular Effects: Epidemiology, Prevention, and Treatment, (17 May 2001); doi: 10.1117/12.426716
Show Author Affiliations
Brian Jason Lund, TASC, Inc. (United States)
Harry Zwick, Walter Reed Army Institute of Research (United States)
David J. Lund, Walter Reed Army Institute of Research (United States)
Bruce E. Stuck, Walter Reed Army Institute of Research (United States)
James W. Ness, Walter Reed Army Institute of Research (United States)


Published in SPIE Proceedings Vol. 4246:
Laser and Noncoherent Light Ocular Effects: Epidemiology, Prevention, and Treatment
Bruce E. Stuck; Michael Belkin, Editor(s)

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