Differential acuity of the two eyes

In order to characterize the phenomenon of differential acuity of the two eyes, the visual threshold (OD and OS) of 180 individuals was measured using a scale whose angular variations were of the same magnitude and equal to 0.05’. The group was within the age range of 10 to 40 years. All subjects had normal ophthalmological examinations, were approximately isometropic, and had refractive errors not exceeding 3 spherical diopters or 1.5 cylindrical diopters. Measurements were made under optimal conditions in the same place and by a single examiner. This permitted obtaining a distribution of 180 acuities for OD and OS. The differences in resolving power detected between OD and OS for each individual were very small. In fact, even resolving power (null differences) was 45%, and visual differences did not exceed 0.10’ in 95.5% of eye pairs. Among individuals whose eyes showed different resolving powers (55% of the sample), there was no correlation between visual acuity and motor sighting dominance.