Changing binocular fusional area with retinal shift in binocular vision

In three-dimensional display systems, binocular disparity must be limited within a certain area, called as "Panum's fusional area". Otherwise, unsuitable binocular disparity can cause double view or eye fatigue. In this study, we measured the binocular fusional areas in central vision, in the case of peripheral visions of retinal eccentricity of 3 degrees and 6 degrees on horizontal meridian, respectively, using a three-dimensional display. The following results were obtained, (1) in each experiment in central vision, peripheral vision of 3 degrees and 6 degrees, the disparity limit in horizontal meridian is larger than that in vertical meridian; the binocular fusional area is symmetrical about horizontal meridian and is not symmetrical about vertical meridian; the nasalward disparity limits are larger than the temporalward disparity limits; therefore, the form of the binocular fusional area is considered as an ellipse off-centered toward the nasal side on the horizontal meridian. (2) The size of the binocular fusional areas increases with the increase of retinal eccentricity, and the increase of disparity limit on horizontal meridian is faster than that on vertical meridian.