Visual fields of cats with cortical and tectal lesions.

When cats were tested for visual field perimetry, the field of vision for each eye separately was from 45 degrees contralateral to 90 degrees ipsilateral. After either bilateral occipitotemporal lesions (with a split of the tectal commissure) or bilateral area 17, 18, and 19 lesions, the cats could see with each eye only from the midline to 90 degrees ipsilateral. A cat that became nearly totally blind as a result of bilateral occipitotemporal decortication had a subsequent tectal split which enabled it to see with each eye from the midline to 90 degrees ipsilateral.