Monocularly programmed human saccades during vergence changes?

Abstract

1. When binocular fixation is shifted to a new target located at a different distance and in a different direction from initial fixation, a binocularly unbalanced saccade occurs at or near the onset of the composite eye movement. Those saccades typically produce good post-saccadic foveation of the target by one eye or the other. 2. Following such saccades, the better-aligned eye is typically as well aimed at the target as after pure versional saccades, but the partner eye deviates much more, thus requiring asymmetrical post-saccadic vergence movement. 3. This phenomenon suggests that during binocular viewing, the retinal eccentricity of a new-target's image from one of the eyes can be used to programme that eye's own saccade, so that it arrives reliably on target; and that the images of that target from both eyes participate in generating the saccadic excursion of the partner eye. 4. The ecologically useful result is rapid achievement of a high-resolution monocular view of the new target, although full binocular foveation is achieved much later.