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The optic fissure, also termed the choroid fissure, is an embryologic structure essential for the morphogenesis of the eye (see Figure. Embryology of the Optic Fissure). Its formation and eventual closure are implicated in the morphogenesis of the iris, ciliary body, retina, choroid, optic nerve, and central retinal artery. It closes in the seventh week of development, and when it fails to close, it results in significant defects, the most prominent of which is coloboma.[1]

Failure of proper closure of the optic fissure can lead to the following defects: Coloboma: A coloboma is a hole or defect in either the eyelid, cornea, iris, lens, ciliary body, zonules, retina, choroid, or optic nerve as a result of incomplete closure of the optic fissure.[18] The frequency is 10 to 20 cases per 100000 infants. In some cases, this problem can be part of a more complex picture that also involves other organs such as, for example, in CHARGE syndrome in which the coloboma correlates with cardiac and facial anomalies, mental retardation, deafness. Since it is a malformation, resolutive drug therapies are not possible. In some cases, good results are obtainable in improving eyesight with the use of lenses and optical aids Optic pits: An optic pit is a depression within the optic nerve as a result of incomplete closure of the optic fissure.[19] This malformation is first described in 1882 by Dr. Wiethe. The optic pit, in about two-thirds of patients, is clinically asymptomatic; but complicated by developing a serous macular detachment, secondary to the accumulation of subretinal fluid, which most frequently appears in the second and third decade of life. However, the treatment of serous macular detachment from the optic pit is still controversial.