part of part of optic stalk optic fissure Develeopment notes: As the eye starts to develop, a gap opens on the underside of each eye bud. This gap provides a way for the developing eye to be nourished. This gap, called the optic fissure, has to close before the eye is fully developed. Coloboma is the incomplete closer of the optic fissure optic foramen surface groove ventral part of optic cup