Eyelid Coloboma

Excerpt

Columba is derived from the Greek word koloboma ("curtailed" or mutilated) and describes a hole or gap in ocular tissue present at birth. The abnormality usually results from incomplete development of the eye in embryonic development. An eyelid coloboma is a congenital full-thickness defect of the eyelid margin; structures that may be affected are the eyelid, iris, lens, ciliary body, choroid, retina, or optic nerve.

Congenital eyelid coloboma can be unilateral or bilateral, involving 1 or all 4 lids. The defect can range from a minor marginal notch to a complete full-thickness absence of the entire eyelid margin, affecting approximately one-third to half of the eyelid. Usually, the upper eyelid is primarily affected, and the most common site of involvement occurs at the junction between the medial and middle thirds of the upper eyelid. Eyelid coloboma is an incomplete form of cryptophthalmos, a congenital condition characterized by eyelid abnormalities due to a failure in differentiation.