Eye Controlled Simulation of Laser Damage on the Retina

A scotoma or blindspot was generated in human subjects using an eye controlled computer display to simulate retinal effects of accidental laser exposure. Visual search time and eye behavior were measured during search for acuity targets while a simulated brightspot or scotoma afterimage blocked the...

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Bibliographic Details
Main Author: Bertera, James H
Format: Report
Language:English
Subjects:
ACCIDENTS
ACUITY
AS878
BEHAVIOR
BLIND SPOT
BRIGHTNESS
COMPUTERIZED SIMULATION
COMPUTERS
CONTROL
DECAY
DENSITY
EXPOSURE(GENERAL)
EXPOSURE(PHYSIOLOGY)
EYE
FOVEA
LASER DAMAGE
LASER HAZARDS
PE6277A
POSITION(LOCATION)
RETINA
SCOTOMA
SEARCHING
SIMULATION
SIZES(DIMENSIONS)
Stress Physiology
TARGET ACQUISITION
TARGET DETECTION
TARGET RECOGNITION
TARGETS
TIME
VISIBILITY
VISION
VISUAL PERCEPTION
WU205
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Description
Summary:A scotoma or blindspot was generated in human subjects using an eye controlled computer display to simulate retinal effects of accidental laser exposure. Visual search time and eye behavior were measured during search for acuity targets while a simulated brightspot or scotoma afterimage blocked the foveal visual information. This simulated laser aftereffect impaired visual search performance 90%-110%. Simulated foveal scotoma deficits were still present when target size, search element density and display brightness improved peripheral visibility. The simulated scotoma probably required subjects to employ the unaffected peripheral retina for target recognition and may have caused disturbances in eye fixation programming. A technique was also developed for simulating the slow decay of a laser induced afterimage. Preliminary data suggests that the subjects tend to look left relative to their normal eye fixation position in order to bring the search target to an area of retina just outside the site of simulated laser exposure; the tendency appeared to be reduced as the simulated scotoma faded. Development of the simulated scotoma technique to evaluate the effects of laser exposure on visual performance in human subjects shows promise because the size, intensity and position on the retina of the simulated exposure can all be controlled with complete safety. The method may have application for demonstrations and training which might serve as countermeasures to the impairments in visual performance caused by central scotomas.