Retinal image smear as a source of information about magnitude of eye movement

A number of experiments were conducted to determine to what extent retinal image smearing during saccades provides information about the eye movement magnitude to the perceptual system. The technique involved obtaining measures of perceived movement when the total visual field was displaced in conjunction with saccadic eye movements. Trials with normal retinal smear were compared with trials on which smearing was greatly reduced or eliminated. The results are interpreted as showing that the absence of normal retinal smear during a saccade increases the uncertainty in the information available to the perceptual system and that this uncertainty results in a tendency to perceive smaller than veridical amounts of movement.