FIXATION DISPARITY AND NEAR VISUAL-ACUITY

Twenty patients having associated heterophoria values of 2 Delta and g reater, as recorded with a Mallett unit, had their near monocular and binocular visual acuities measured. in the latter case, measurements w ere taken both with the associated heterophoria corrected by prisms an d without prism correction. Bradford Near Vision charts, specially des igned to measure visual acuity at near in seconds of are, were used in the acuity measurement. The improvement of binocular acuity compared with monocular acuity was less than would occur in normal subjects wit hout associated heterophorias. When the associated heterophorias were corrected with prisms the improvement in binocular over monocular acui ty was similar to that found in normal subjects, with zero associated heterophoria readings.