Fixational eye movements and microsaccades in binocular coordination
Final Report Abstract
Fixational eye movements can be divided into slow components, drift and tremor, and microsaccades that occur with an average rate of 1 per second and share kinematic properties with larger saccades during free viewing. In this project we investigated the potential role of fixational eye movement and microsaccades for binocular coordination, for 3D smooth pursuit, and attentional shifts between different depth planes. In the first part of the project, we analyzed the rate and orientation statistics of binocular and monocular microsaccades during attentional shifts between different depth planes. Based on a paradigm by Atchley et al. (1997), we could not find specific effects of binocular or monocular microsaccades under these attentional shifts between depth planes. We conclude that it is unclear whether microsaccades are sensitive to depth manipulations. In the second part of the project, we investigated possible contributions of microsaccades to the correction of disparity error under 3D smooth pursuit. Here we developed an experiment that was derived from Zhou and King’s (1998) monocular pursuit paradigm. However, in our experiments, we were unable to demonstrate a functional role for microsaccades, even after experimentation with numerous variants that were outlined in our grant proposal. In the final part of the project, we planned to study perceptual fading under binocular retinal stabilization. Here, we tried to find an optimal match between our experiment design and the available technical equipment. However, no substantial fading could be induced experimentally. Therefore, we could not investigate how microsaccades would potentially contribute to counteract perceptual fading under binocular retinal stabilization.
