Abstract
Abstract: :
Purpose: To investigate the influence of the vergence amplitude, visual field position and vertical horopter tilt on the filling–in latency of stereoscopically presented targets; in addition, to compare the results between dichromats and trichromats. Methods: 7 dichromats and 7 trichromats were selected with stereo acuity of at least 50 seconds of arc and normal corrected near visual acuity. Vergence amplitude determined prior to tests. Dichromats classified with the HRR test. Stimuli presented on a 17 inch monitor with gray background. Anaglyphs created using two circular patches – one blue, one orange – of 0.3° diameter, 0.5° disparity and 6° eccentricity from central fixation point. The blue filter was used at the right eye and the orange filter at the left eye to produce stereo stimuli. Targets presented at the visual field midline, 90° and 270° with crossed and uncrossed disparity. 32 trials were performed for each target possibility. Results: There was no significant difference between dichromats and trichromats. Both groups show significant longer filling–in latency for targets presented at the lower visual field position compared to the upper position. There was no significant latency difference for targets presented near or far from the vertical horopter or between crossed and non crossed target disparity in any group. Conclusions: Dichromats and trichromats present similar performance on most visual tasks. This was confirmed in our experiment. Despite the large variation in vergence amplitude found among our subjects, this feature and the known tilt of the vertical horopter seem to have no influence on the perceptual filling–in latency of stereoscopically presented targets.
Keywords: binocular vision/stereopsis • perception • color vision