Aplasia of the optic nerve is a congenital anomaly rarely seen except in grossly malformed eyes. Cords1 (1923) said that it is one of the greatest rarities. A brief review of the embryology of the optic nerve will facilitate understanding the condition.2 By the 2.6 mm. stage of the embryo (fig. 1) the optic pits are becoming visible on each side of the anterior end of the neural canal. These pits rapidly grow out, forming by the 4 mm. stage the hollow, bulbous optic vesicles, the cavities of which are connected with the lumen of the neural canal by the short optic stalks. At the 4.5 mm. stage (fig. 2) the fetal fissure begins to form by invagination of the optic vesicles in a ventrolateral position. The outer wall of each vesicle, which is to become the retina, has by this time increased to several cell layers in