Abstract
Abstract: :
Purpose: We have previously reported that the amount of binocular summation was affected by target sizes using light–sense perimetry. In this study, we investigated the effect of binocular summation for both detection and resolution thresholds using several kinds of parallel line targets. Methods: Detection and resolution thresholds were measured using the Octopus 201 combined with the space synoptophre. Three types of parallel line targets (10', 2.5' and 1.43' visual angles) were used. We measured the monocular and binocular detection and resolution thresholds under the same binocular fusion stimulation conditions in seven normal subjects. Using the SARGON program, we designed a program to test 27 points, 17 of which were located in the central 6° visual field and ten on the horizontal meridian subtending 8°, 10°, 12°, 16° and 20°. Results: The differences between the detection and resolution thresholds were not significantly different using a 10' width parallel line target. However, the resolution thresholds were higher than the detection thresholds using 2.5' and 1.43' width parallel line targets. The binocular summation ratio of resolution and the detection thresholds showed no significant difference when the 10' width line target was used. When 2.5' and 1.43' width line targets of were used, the binocular summation of resolution threshold was higher than the detection threshold. The binocular summation ratio of the detection threshold increased with the narrowing of the line width at the fovea. With increasing eccentricity of stimulus presentation from the fovea, the binocular summation ratio of the detection threshold was not significantly influenced by the line width, and remained relatively constant. The binocular summation of the resolution threshold was highest using the 1.43' width line target, and increased with increasing eccentricity from the fovea. Conclusions: The binocular summation of the detection and resolution thresholds varied as a function of the line width. The binocular summations of the resolution threshold increased depending on the eccentricity from the fovea.
Keywords: binocular vision/stereopsis • visual fields • perimetry