One of three patients with cerebrogenic hemianopia showed residual light and movement perception in the "blind" field, whereas two other patients showed no light perception. Although the first case is compatible with the concept of extra-cortical photo sensitivity or alternative explanations, the other two cases give no support to this concept. A fourth patient, blind from bilateral occipital lesions of traumatic origin, was shown to be capable of detecting motion and the orientation of stripes although unable to identify shapes or forms.