Akademik

1. The apparent displacement of an object that follows a change in the position from which it is viewed. 2. See phi phenomenon. [G. alternately, fr. par-allasso, to make alternate, fr. allos, other]

- binocular p. the difference in the angles formed by the lines of sight to two objects situated at different distances from the eyes; a factor in the visual perception of depth. SYN: stereoscopic p..

- heteronymous p. the apparent movement of an object toward the closed eye; noted in exophoria.

- homonymous p. the apparent movement of an object toward the open eye when one is closed; noted in esophoria.

- stereoscopic p. SYN: binocular p..

- vertical p. the relative vertical displacement of the image when each eye is closed in turn; seen in vertical diplopia, or heterophoria.

par·al·lax 'par-ə-.laks n the apparent displacement or the difference in apparent direction of an object as seen from two different points not on a straight line with the object <motion \parallax governs the way objects appear to move when the eyes or head are shifted (Edmund Andrews)>