Human response to cyclofusional stimuli containing depth cues.

The cyclofusional response to stimuli containing depth cues was studied. Eye positions were monitored by an objective, binocular, eye movement measuring technique while a psychophysical method was used to measure the stereoscopic responses. We found that the overall response contains both stereoscopic and cyclofusional components and that the cyclofusional response includes a large nonmotor, or sensory, contribution. The composition of the response was unaffected by changes in stimulus size. Increased stimulus complexity elicited larger cyclotorsional eye movements and diminished the amount of perceived inclination which was observed in the fused percept.