Most famous for creating the Ishihara colour test for colour blindness in 1918. The test consists of a number of colored plates containing a circle of dots randomized in color and size. Within the randomized pattern are dots which form a number visible to those with normal color vision and invisible, or difficult to see, for those with a red-green color vision defect. The full test consists of thirty-eight plates, but the existence of a deficiency is usually clear after a few plates. He also contributed heavily to the study of myopia and trachoma. Educated at Tokyo University and afterward embarked on military service. As a military physician he held the rank of a chief physician general.