Conjugate lateral eye movements and cognitive mode: blindness as a control for visually-induced oculomotor effects.

The relationship between lateral eye movement directionality and type of cognitive task was investigated in a single blind subject with septo-optic dysplasia. Results from an 80-item test showed that rightward eye movements were significantly associated with verbal tasks and leftward eye movements with spatial tasks. As visual influences on oculomotor behaviour were eliminated, the findings suggested that lateralized eye movements might have arisen as a consequence of asymmetrical activation of cognitive origin triggering the frontal eye field orienting mechanism.