SUPPRESSION OF CONTRAST SENSITIVITY DURING EYELID BLINKS

Each blink of the eyelids is associated with a concurrent suppression of vision that lasts as long as 200 msec. Saccadic eye movements are also associated with a concurrent suppression of vision. Previous studies suggested that blink and saccadic suppression may be the result of a single mechanism. Volkmann, Riggs, White and Moore [(1978) Vision Research, 18, 1193-1199] demonstrated that saccadic suppression is most evident for low spatial frequency stimuli. However, the effect of stimulus spatial frequency on blink suppression has not been evaluated. If blink suppression and saccadic suppression result from a single mechanism, then blink suppression should also exhibit its greatest effect at low spatial frequencies. The purpose of this study was to determine the effect of stimulus spatial frequency on blink suppression. The stimulus was a sine-wave grating presented at different times after the blink. Psychometric functions were produced from the data for each post-blink, stimulus onset time and a Weibull function was fit to the data to determine threshold. The magnitude and duration of blink induced contrast sensitivity suppression was found to depend on the spatial frequency of the stimulus employed (similar to saccadic suppression). This is further evidence that a single mechanism may produce both blink induced visual suppression and saccadic suppression.