Physical light stimuli, if absorbed by the photosensitive substance or substances in the cones, generate impulses in the photoreceptors. These impulses pass through the centripetal bipolar cells and are transmitted to the ganglion cells, along whose axis cylinders they are finally conveyed to the brain. It is possible that pathological changes in this retinocerebral pathway may disturb the normal trichromatic function quantitatively and qualitatively. In such acquired lesions of color perception, not only is color vision disturbed but visual fields are also affected. Therefore, the symptoms of acquired color-vision defects are usually very complicated. They may differ from those of congenital disturbances of color vision, the symptoms of which are so characteristically uniform that a clear-cut classification can be applied. As far as the acquired color-vision defects are concerned, our knowledge is very limited and incomplete and we do not have widely approved classification. Köllner (1912)1 believed that acquired