Blindness

{blind/-nes) [AS., blind”]. Want of vision. B., Color-, imperfect color-perception. This condition is found in about 4 per cent, of persons, is more frequent in men than in women, and is probably due to non-exercise of the color-sense. Complete Color-B. is very rare, the different colors probably appearing as different intensities or shades of white light. In Partial Color-B. defective perception of red is the most frequent, green, blue, and yellow, respectively, being next in order. Tests for Color-B. usually consist in matching and cla ifying colored yarns. B., Cortical, blindne due to lesion of the cortical center of vision. B., Day-. See Nyctalopia. B., Mind-. See B., Psychic. B., Moon-, a rare condition of retinal anesthesia said to be due to exposure of the eyes to the moon’s rays in sleeping. B., Night-. See Hemeralopia. B., Object-. See Apraxia. B., Psychic, lo of conscious visual sensation from destruction of the cerebral visual center; there is sight but not recognition. B.,Snow-, photophobia and conjunctivitis due to exposure of the eyes to the glare of sunlight upon snow. B., Word-. See Aphasia. 152