Disparity-induced vergence responses in normal and strabismic subjects

Latencies of vergence responses were obtained by presenting vertical line stimuli for 0.5 sec to the fovea of one eye and to various retinal locations of the other eye of four subjects with normal binocular vision, one exotrope with normal retinal correspondence, and four esotropes with anomalous correspondence. Vergence latencies were larger for squinters than nonsquinters and were especially long for the squinters with anomalous correspondence. For three of the four anomalous corresponders, the direction of the vergence movement (convergence or divergence) was based on the location of the stimulus with respect to the anomalous retinal point in the deviating eye--not with respect to the fovea as occurred for the subjects with normal correspondence.