Cyclopia (also called cyclocephaly or synophthalmia) is a birth defect. Cyclopia is characterized by a failure of the prosencephalon to separate the two orbits (eyes). This leads to the formation of a central deformed eye and an absence of a nasal cavity. It causes can be either genetic, or as a result of an exposure to poisons. The term "cyclopia" comes from Cyclops, a giant one-eyed creature the Greek Greek mythology.