The rhino-optical phenomenon: ocular parallax and the visible field beyond the nose

One of the consequences of the noncoincidence of the nodal point and the center of rotation of the eye is the disappearance of targets near the limit of the nasal visual field when the monocular gaze is directed towards them. This ocular parallax phenomenon, which we measured in six adult subjects, is discussed in terms of its usefulness in demonstrating ocular parallax in a classroom situation. Also, a possible laboratory exercise is suggested.