The binocular vision of human beings is given by the almost complete superimposition of the monocular visual fields, which allows a finer perceptual discrimination of the egocentric localization of objects in space (stereopsis) but only within a very narrow band (the horopter). Before and beyond it, diplopia and confusion are present, so that a physiologic (cortical) suppression is necessary to avoid them to become conscious. The geometry of the horopter and its physiologic implications (Hillebrand's deviation, Kundt's partition, Panum's area, stereoscopic vision) are analyzed, as well as some clinical aspects of the normal binocular vision (simultaneous perception, fusion, stereoscopic vision) and of adaptations to abnormal states (pathologic suppression, amblyopia, abnormal retinal correspondence).
Vision, binocular; Amblyopia; Vision disorders; Visual perception; Depth perception
