Oculomotor responses to perspective grid line drawings

Purpose. Can disconjugate eye movements be triggered by pictorial depth cues? If they could, this would facilitate eye pointing to three-dimensional displays. Method. Eye movement responses were measured as subjects shifted their gaze from a central fixation point to a suddenly appearing target in a different direction and at a different perceived depth on a perspective background. Both monocular and binocular viewing conditions were tested. The subjects' task was to move their gaze, as quickly and as accurately as possible, to a small target, which could appear 10° up, down, left or right of an initial central fixation point. The background consisted of a grid superimposed on two inner surfaces of a cube, one straight ahead of the subject and the other appearing to come towards the subject. The central fixation point was superimposed on the square grid, which appeared to be straight ahead of the subject. The target was superimposed on the perspective grid, which appeared to form a surface towards the subject. Results. It contrast to Enright's (V R, 1987) findings, subjects made no measurable vergence eye movements under either monocular or binocular viewing conditions. Similarly, no saccadic disconjugacy was found. Conclusions. The findings have implications for the use of eye pointing as an effective method of interacting with three-dimensional computer displays, where the depth information could be provided by perspective cues. For example, the extent to which the binocular point of foveation of different depth planes can be differentiated is of primary importance. Secondly, the speed with which the binocular point of foveation can be moved between two depth planes affects how fast eye pointing can be achieved