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In order to develop the effective evaluation system for the fatigue of operator's visual system in long term operation, the experiments were carried out utilizing perceptual time duration of motion aftereffect (MAE), critical flicker frequency (CFF) and the near point (NP) measurement. The MAE was measured using rotated spiral figure displayed on a CRT screen. To generate visual fatigue, a signal detection task in randomly displayed alphabets was used. After the task, MAE duration, CFF and NP were increased. It is supposed that the visual fatigue generated by the experimental task affects motion processing system of visual cortex. Results suggest that the MAE can be an effective tool for visual fatigue evaluation.

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The aim of this experiment is to evaluate visuospatial and visuomotor cognitive function of the normal healthy young subjects. Estimation of object in motion in blinded spatial environment requires focused attention involving retrospective and prospective memory directly relating to visual cognitive functions.The task was carried out on a computer screen where the subjects followed an object in motion that disappears at specified distance and triggering the stop button when the object reaches a specified target.Blind distance and speed variables were used as criteria to determine the cognitive functions in the subjects. Two groups of five subjects performed a visual motion task with no feedback; namely blind condition (object do not reappears upon target triggering) and with feedback; namely visible condition (object reappears upon target triggering) in the reverse order for each group. Results showed object's longer disappearance duration (wider blind distance) affects deterioration in prospective memory more compared to narrower blind distance and the speed of the object has minimal affect in estimating the target.