Fixation Disparity and the Interaction of Foveal and Non-Foveal Fusion

Abstract

The objective misalignment of haploscopic vernier lines induced by some oculomotor imbalance (e.g. prism strain, heterophoria) is called fixation disparity (Fig. 1; Ogle et al. 1967). As a matter of fact fixation disparity is to correspond to some mismatch of the fusion pattern in the test person’s subjective space. How can this mismatch be processed in the test person’s visual system? Can this be done by straightforward sensory fusion or is it achieved by partial suppression of bifoveal vision? The interactions between fixation disparity and foveal suppression have been discussed in the literature (Ogle et al. 1967) but — to our best knowledge — nobody really tried to show them.