Exact knowledge of binocular coordination in human subjects has been obtained largely with the head held erect and with the fixation point symmetrically placed before the eyes in a horizontal plane. Rotational responses (vergences and versions) have been assumed to correspond with the rotational stimuli. The exceptions to these restrictions are reviewed.
A tilting haploscope has been designed and constructed which differs from other haploscopes previously described in that: (1) it enables one to tilt the plane of regard (the plane containing the centers of rotation of the two eyes and the fixation point) about the base line (the line connecting the centers of rotation ofthe two eyes); (2) the subjects head can be tilted about the base line; and (3) a means of recording rotational responses is provided.
The optical and mechanical features are described as well as the method of positioning the subject’s head.
Preliminary results using five subjects suggest that the ACA ratio decreases when the plane of regard is elevated, and that the ACA is not effected by the tilt of the head. Rotation of the eye lags the stimulus increasingly as the stimulus is moved peripherally with maximum values up to approximately ½ deg.
HENRY A. KNOLL, "Research Tilting Haploscope," J. Opt. Soc. Am. 49, 1176-1176 (1959)