A nutritional condition produced by a deficiency of VITAMIN A in the diet, characterized by night blindness and other ocular manifestations such as dryness of the conjunctiva and later of the cornea (xerophthalmia). vitamin a deficiency is a very common problem worldwide, particularly in developing countries as a consequence of famine or shortages of vitamin A-rich foods. In the united states it is found among the urban poor, the elderly, alcoholics, and patients with malabsorption. (From Cecil Textbook of medicine, 19th ed, p1179)