Homonymous bilateral hemianopsia: electrophysiological study of a case

Described is a case of bilateral homonymous hemianopsia with macular sparing, resulting from head trauma. The case presented lesions of the occipital visual areas which involved entirely the left hemisphere and only partially the right hemisphere. VEP were obtainable only from electrodes placed on the right hemisphere with both right eye and left eye stimulation. VEP mapping showed that each eye projects macular fibres towards functional areas of the right occipital hemisphere. Electrophysiological examination confirmed objectively and for the first time in man the theory of "double cortical macular representation". Clinical implications of this finding are discussed.