Vergence eye movements facilitated by saccades.
This study was carried out to determine whether the vergence velocity is influenced or not by the richness in visual cues for the perception of depth and by the association of saccade. Vergence eye movements associated with and without saccades were recorded in 4 normal subjects with two CCD cameras in both dark and illuminated rooms. Subjects fixated between the targets, which differed in direction and in depth. The peak vergence velocity was 50 degrees to 90 degrees per second for 10 degrees vergence change and 30 degrees to 70 degrees per second for 5 degrees vergence change. Transient vergence change was found during horizontal or vertical saccade. Even after deleting this transient vergence change, the peak velocity of vergence became faster when it was associated with vertical or horizontal saccade. Trajectories of fixation locus were calculated when the vergence and saccade were required simultaneously. Whether or not the room was rich in visual cues for depth perception seemed to have no effect on vergence velocity. Blinking also speeded up divergence. Most eye movements in daily life are the combination of vergence and saccade, and this vergence facilitation by saccade helps to attain prompt binocular fixation on the new target.
Oohira
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A
Department of Ophthalmology, University of Tokyo School of Medicine, Japan.
D000328:Adult; D001767:Blinking / Q000502:physiology; D003290:Convergence, Ocular / Q000502:physiology*; D003867:Depth Perception; D005133:Eye Movements / Q000502:physiology*; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D012438:Saccades / Q000502:physiology*; D014741:Video Recording; D015348:Vision, Binocular