Contrast sensitivity during saccadic eye movements

The experiment measured contrast sensitivity of three human observers to sinusoidal gratings presented in 10 msec exposures. The gratings were presented to the steadily fixating eye and during 6° horizontal saccades. Experimental conditions of viewing in a Ganzfeld reduced possible effects of contour masking. The use of horizontal gratings minimized retinal smear. Results showed a significant suppression of sensitivity (more than 0.6 log unit of contrast) to low spatial frequency gratings presented during saccades. The magnitude of saccadic suppression decreased as spatial frequency of the gratings increased. We conclude that optical and neural effects combine in normal viewing to produce saccadic suppression. Minimizing the optically originating effects of contour masking and retinal image smear failed to eliminate the considerable impairment of vision that occurs during a saccadic eye movement.