Recovery of visual functions in patients with cerebral blindness. Effect of specific practice with saccadic localization

Abstract

Patients with homonymous visual field defects after damage to the geniculo-striate pathway were forced to make saccadic eye movements to light targets presented briefly in their perimetrically blind regions. This specific type of saccadic localization led to an increase in visual field size in the region subjected to this practice. Visual acuity and color identification also improved in the restored region, provided that the lesion was mainly limited to the striate cortex. The enlargement of the visual field strongly depended on a specific practice. The degree of recovery was related to the sharpness of the visual field border. In patients with a rather shallow gradient of light sensitivity in the area between the intact visual field and the scotoma, a fairly good recovery was obtained, whereas in patients with a steeper gradient the enlargement of the visual field was small. It is suggested that recovery takes place at the level of the striate cortex and is probably mediated by the retino-tectal pathway.