The effect of occlusive patching on visually-directed tasks.
OBJECTIVE
Occlusive patching is used to treat a variety of ocular conditions. A paucity of literature exists regarding the effects of occlusion on functional tasks and driving performance. We investigated the immediate effects of occlusive patching on a variety of visually dependent tasks as well as driving performance on a simulator.


METHODS
Thirty normally sighted subjects were examined in a prospective randomized manner. All subjects underwent a complete medical history and eye examination. All subjects performed a variety of near tasks and drove a driving simulator with and without patching. The tasks included traditional clinical depth tests, tests of visual memory, scanning, and tracking, and gross and fine-motor abilities. All subjects filled out a questionnaire relating to their perception of the effects of patching on functional tasks and driving ability.


RESULTS
Visual memory, scanning, tracking, and perceptual constancy were unaffected by patching. However, there were significant differences between the patched and unpatched conditions for four of five of the three-dimensional visual coordination tasks. Eight of 19 (42%) of the fine-motor tasks and 4 of 9 gross-motor tasks (44%) showed significant differences between the patched and unpatched conditions. A greater frequency of out of lane events and more abrupt braking profiles were seen when subjects drove monocularly rather than binocularly.


CONCLUSIONS
Sudden occlusion immediately changes perceptual ability by decreasing visual field and eliminating stereoacuity. This has important implications for the performance of everyday tasks.
Gupta
Balaji
B
Department of Ophthalmology and Visual Sciences, The University of Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
Paliga
Jennifer
J
Laderman
Denice J
DJ
Szlyk
Janet P
JP
D000293:Adolescent; D000328:Adult; D003867:Depth Perception / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011597:Psychomotor Performance / Q000502:physiology; D012016:Reference Values; D012683:Sensory Deprivation / Q000502:physiology*; D013647:Task Performance and Analysis; D015349:Vision, Monocular / Q000502:physiology*