Accession Number : ADA237970


Title :   Eye Controlled Simulation of Scotoma Effects on the Retina


Descriptive Note : Annual rept. (Final) 3 May 1986-2 Sep 1989


Corporate Author : EYE RESEARCH INST OF RETINA FOUNDATION BOSTON MA


Personal Author(s) : Bertera, James H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a237970.pdf


Report Date : 01 Jul 1990


Pagination or Media Count : 20


Abstract : Scotoma simulation is useful for evaluating visual loss or disruption (eg from the aftereffects of accidental laser exposure or retinal disease) because it allows testing the size, position and shape of scotomas in normal subjects under controlled conditions. Human eye movements, made during visual performance tasks, were used to move an obscurant or mask to display areas corresponding to the fovea. These real-time, eye controlled scotoma movements eliminated central vision and compelled the subjects to adapt by using peripheral vision and eccentric fixation. Adaptation to the simulated scotomas was evaluated by measuring changes in the eye fixation duration, saccade length and the eye position relative to instructed targets. Rapid development of eccentric eye positions, the principal means of compensating for the loss of central vision, showed that subjects are able to optimize the location of the scotoma with the higher receptor density. During and after adaptation, the presence of a simulated scotoma caused grossly distorted eye fixation patterns when compared to normal fixation control. Abnormal patterns were reduced as subjects became more experienced with the simulated visual losses, but, there were persistent drift movements, dispersion of eye fixations and error fixations with the scotoma especially under stress from accelerated pacing. Whether there is residual visual impairment after adaptation is dependent on the size of the scotoma, the length of the adaption period and the visual demands of the task.


Descriptors :   *RETINA , PERIPHERAL VISION , DENSITY , MEASUREMENT , HUMANS , DISEASES , DISPLAY SYSTEMS , RESIDUALS , PATTERNS , LOSSES , VISION , VISUAL PERCEPTION , EYE , EXPOSURE(PHYSIOLOGY) , LASER HAZARDS , MASKS , SENSE ORGANS , ABNORMALITIES , FOVEA , ECCENTRICITY , VISUAL DEFECTS , EYE MOVEMENTS , ACCIDENTS , POSITIONING REACTIONS , CONTROL , SIMULATION


Subject Categories : Anatomy and Physiology
      Medicine and Medical Research


Distribution Statement : APPROVED FOR PUBLIC RELEASE