Computed tomography (CT) is useful for demonstrating a lesion of the optic pathway, because a slice of the brain almost parallel to the optic pathway can be viewed and the relationship between the optic pathway and the extent of the lesion can be demonstrated. We studied 53 cases of homonymous hemianopia by CT. In 85% of our cases, positive CT findings were obtained. When the lesion was in the occipital lobe, correlation between the size of the lesion and the type of visual field defect was observed.