Eye dominance in binocular viewing conditions.

Abstract

Different degrees of eye dominance may need to be considered when comparing monocular and binocular performance or estimating binocular summation effects. The purpose of this study was to explore eye dominance under binocular viewing conditions and observe gradual differences in preference. Two binocular eye-dominance tests were evaluated and compared to the hole-in-the-card sighting test. The first experiment was based on a binocular sighting test. The second originated from the variable-angle mirror test, utilizing physiological diplopia to determine which eye dominates the binocular percept. The participants were 32 healthy subject with normal sight. For both experiments there were plausible effects of different degrees of eye dominance affecting how the subjects positioned or perceived the scene. The outcomes were supported by a statistically significant correlation with an interocular difference in sensitivity to degraded visibility. A statistically significant correlation was found between the hole-in-the-card test and the variable-angle mirror test (r = 0.527, p < 0.01). The experiments confirm the plausible occurrence of forms of eye dominance under binocular viewing conditions. The correlation with the hole-in-the-card test was weak to moderate, due to factors that appear to be related to testing and viewing conditions. Interocular differences in sensitivity to blur appear to be a useful factor in further grading of eye dominance.