Measuring the full limits of Panum's fusional area in retinal fovea

Previous studies on the limits of Panum's fusional area have focused only on the horizontal and vertical meridians. For this reason, we measured the full limits of Panum's fusional area in eight different directions from 0 degree to 360 degrees using a step of 45 degrees in the retinal fovea with a 3D display device. The following results were obtained: (1) The horizontal limit of Panum's fusional area in retinal fovea was larger than the vertical limit; (2) The limits of Panum's fusional area were almost symmetrical about the horizontal meridian; (3) The nasalward limits were obviously larger than the temporalward limits; (4) In the nasal side of the retina, the limits increased in a monotonic fashion; however in the temporal side, the limits had no obvious change.