A Statistical Analysis of Attentional Effects on Drift Eye Movements

Recent studies have demonstrated a close relationship between the frequency of microsaccades and covert attention shift. However, there are no arguments of attentional effect on drift movements during attentive or inattentive fixation. We examined whether visual attention has any influence on drift eye movements using statistical analysis of a time series of fixation eye movements. The results indicated that the power in the 3-4 Hz frequency range was enhanced when visual attention was dispersed over the parafoveal visual field. Furthermore, the amplitudes of the drift eye movements were reinforced immediately after the microsaccades, especially after square-wave jerks. These results suggest that microsaccades and drift eye movements are both controlled by higher order brain functions to acquire detailed visual information from the peripheral vision.