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A. Wakayama, C. Matsumoto, K. Ohmure, Y. Shimomura; Monocular and Binocular Reaction Time Difference Affected by Target Size and Eccentricity in Automated Kinetic Perimetry. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5896.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the difference in reaction time (RT) between monocular and binocular conditions affected by targets size and retinal eccentricity in automated kinetic perimetry.
RTs were measured under both monocular and binocular conditions in six normal volunteers (age range: 24-29 years) by the automated perimeter Octopus 101. When measuring binocular RT, we specially equipped the automated perimeter Octopus 101 with a small infrared video camera to control binocular fixation. Target sizes used were 0.108° and 0.216° of visual angle. All test vectors were located at 16 positions at 0°, 5°, 15° and 25° eccentricities on the oblique meridians. Within the same eccentricity, two vectors were presented in the opposite directions along one of the concentric circles toward the horizontal meridian with a velocity of 3 deg/s. Each vector was tested six times for each target size.
Binocular RTs were shorter than monocular RTs for both target sizes at all four eccentricities within the central 25° of visual field (p<0.01). At 15° and 25° eccentricities, monocular and binocular RTs showed a greater difference with target size 0.108° than with target size 0.216° in all subjects (p=0.02) , whereas no difference was observed at 0° and 5° eccentricities. Significant difference was observed between 0° and 25° eccentricities for both monocular and binocular RTs, and the RT increased with eccentricity by 3 ms per degree on average. However, with the target size 0.216°, monocular and binocular RTs did not differ significantly at any of the four retinal eccentricities.
The difference in RT between monocular and binocular conditions is significantly affected by target size and retinal eccentricity. Particularly with smaller target size, binocular RT decreased more significantly in the peripheral retinal area than monocular RT. This observation reflects that, when the task of cognition has become more difficult, binocular vision facilities visual processing function more efficiently than monocular vision.
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