Am Orthopt J 50:96-101 (2000).
The Evolutionary Dichotomy of Human Nasotemporal Disparity
The evolution of frontally placed eyes in predatory animals necessitated the development of a conjugate ocular pursuit system that retains a nasal pursuit bias with respect to the visual world. This hemispheric binocular pursuit system supersedes a primitive subcortical system that is operative in lateral eyed animals, but retains its inherent nasotemporal disparity. The dichotomy between this binocular and monocular nasotemporal disparity reflects the telencephalization of binocular vision and the superimposition of binocular motion detection upon the primitive, diencephalic horizontal motion detection system (the NOT) that subserves monocular nasotemporal disparity.