Smooth Eye Movement To Track Conditions, The Sensitivity Of Visual Space

In the field of visual research, eye movement research provides valuable information of eye physiological and motion parameters to both basic scientists and clinicians. To the neurobiologists, it provides objective basis to the study of neural mechanism. Abnormalities of ocular motility are also clues to diagnose relative diseases.Smooth pursuit eye movement is one of the eye movements, which is to bring slow pursuit objects of interest in the visual field into the fovea and keeps eyes moving simultaneously with the pursuit of targets. During the pursuit, visual attention will be allocated to the target of pursuit, meanwhile, peripheral stimulus can also be perceived in certain spatial distances. It has been proved that the peripheral visual sensitivity during smooth pursuit will be affected by many factors, such as the orientation, speed, color, spatial frequency, and contrast of the stimulus and so on; some increase of sensitivity may have its origin in the neural mechanism of the parvocellular pathway.The visual spatial sensitivity and spatial allocation of attention in smooth pursuit eye movement were mainly studied in this thesis. We adopted eye tracking technology, investigated the recognition accuracy and response time of the peripheral stimulus (T or L) presented upper or lower, forward or backward of the pursuit direction under different spatial distances when targets were tracked accurately. The results indicated that the visual spatial sensitivity decreased with the increase of spatial distances in both smooth pursuit and fixation tasks; what's more, visual spatial sensitivity produced by the horizontal stimulus is higher than that produced by the vertical stimulus. The recognition performances in smooth pursuit eye movements were worse than those in the fixation task, and the response time was obviously longer. The recognition accuracy and response time had no distinct differences between the letters presented forward and backward the pursuit direction, which showed that visual sensitivity had nothing to do with the stimulus direction, which means the focus of attention during smooth pursuit, is centered on the tracked target with no appreciable lead or lag.