Visual Stability during Saccadic Eye Movements

Abstract

We frequently reposition our gaze by making rapid ballistic eye movements called saccades to position the fovea on objects of interest. While the strategy is highly efficient for the visual system, allowing it to analyze the whole visual field with the high resolution of the fovea, it poses several problems for perception. Saccades cause rapid, large-field motion on the retina, potentially confusable with large-field motion in the external world. They also change the relationship between external space and retina position, confounding information about visual direction. Much effort has been made in recent years to attempt to understand the effects of saccades on visual function. Electrophysiological, imaging, and psychophysical evidence suggests that saccades trigger two distinct neural processes: a suppression of visual sensitivity, specific to motion analysis, probably mediated by the magnocellular pathway, and a gross perceptual distortion of visual space just before the repositioning of gaze. While our knowledge of how the visual system copes with the potentially damaging effects of continual saccadic eye movements has increased considerably over the past few decades, many interesting avenues of research remain open.