Indexed on: 17 Nov '10Published on: 17 Nov '10Published in: Vision Research
To assess how target size and eccentricity affect binocular summation (BS) of reaction time (RT) at suprathreshold level, we measured RT using targets of 0.108° and 0.216° at four eccentricities (0°, 5°, 15°, 25°) in six normal volunteers. The difference between the monocular/binocular RT differentials for both sizes significantly increased in the periphery (P<0.05). The smaller target required significantly longer monocular RT at 25° (P<0.01) and generated greater neural summation than the larger target (P<0.01). This suggests that when monocular function has reached its limit in visual processing in the periphery, BS increases, facilitates visual processing, and shortens binocular RT.