Zero retinal image disparity: a stimulus for suppression in small angle strabismus.

Suppression was examined with binocular perimetry in patients with small angle strabismus. Suppression stimuli were presented to the fovea of the fixating eye or 5 degrees nasal or temporal from the fovea. Suppression was found in the deviating eye of patients with normal or anomalous correspondence at retinal points corresponding to the retinal locus of the suppression stimulus. Suppression was demonstrated on both the nasal and temporal hemiretina of the deviating eye. Results indicate that zero retinal disparity is a strong stimulus for suppression in the central and peripheral visual field of patients with small angle strabismus.