Restitution of visual field in patients with damage to the geniculostriate visual pathway

Previous experiments have investigated the effect of specific practice on partially blinded monkeys after striate cortex lesions. Similar procedures were adapted for patients suffering homonymous field defects due to geniculostriate damage. Both methods, light detection and saccadic localization, led to an enlargement of the visual field. The amount of this enlargement depended on the eccentricity of the field border as well as on the level of light sensitivity in the region between the intact field and the scotoma. Recovery of visual field included the reappearance of various visual functions (e.g. visual acuity, color identification). In periods without training visual field did not recover. It is hypothesized that recovery can take place at the level of the striate cortex, and is mediated by structures interacting with the striate cortex, e.g. the superior colliculus.