TIME ON TASK AND BLINK EFFECTS ON SACCADE DURATION

Changes in saccade duration, saccade amplitude and slope of the regres sion line relating amplitude and duration were assessed during a 2 hou r air traffic control simulating task. Mean duration significantly inc reased as a function of time on task (TOT). Saccade amplitude decrease d during the beginning part of the two hour period, increased in the m iddle and decreased in the final part of task performance. Differences in saccade duration were also assessed for saccades occurring during and independent of eye blinks. When matched for amplitude, electroocul ographically measured saccades occurring during a blink were significa ntly slower than those occurring independent of a blink. Our results s uggest caution in interpreting saccade velocity change as an index of 'fatigue' since most of the reduction in average saccade velocity may be secondary to increases in blink frequency.