Saccadic compression can improve detection of Glass patterns

Around the time of saccadic eye movements, briefly presented stimuli are seen to be displaced from their real positions. The direction of the displacement is always towards the saccadic target, resulting in a compression of visual space (Nature 386 (1997) 598). To examine whether the compression may be used by the visual system to aid performance, we measured sensitivity for detecting horizontal and vertical Glass patterns around the time of saccades. Sensitivity to widely spaced horizontal Glass patterns improved slightly during the period just prior to making a horizontal saccade, while sensitivity to vertical patterns was impaired by the saccade. The results provide further evidence for compression in the direction of the saccade at saccadic onset, and show that it does not only affect the apparent position of visual stimuli, but can also improve performance on a visual task.