Microsaccades are rapid and involuntary fixation eye movements. Previous studies have shown that shapes of fixation targets affect microsaccades rate. However, other characteristics of microsaccades have not been analyzed. Here, we investigated the relationship between target shapes and characteristics of microsaccades. Subjects gazed at one of the seven targets, which was composed from a point, a circle, and a cross, for 10 sec. The results indicate that the relationship between amplitude and peak-velocity of microsaccade had no correlation with target shapes, while there were some pairings that have significant differences in the relation between amplitude and frequency. The differences between point-only or point-and-cross target and circle target were salient. When point-only or point-and-cross target was presented, amplitude became small and frequency increased. They were reversed when circle target was presented. These results suggest that microsaccades are controlled to maintain the integration value of amplitude and frequency.
