A Coloboma is a full-thickness defect of the eyelid margin that occurs congenitally.1 The defect may be unilateral or bilateral, involving one or all four eyelids and may vary from a small notch of the lid margin to a complete absence of the entire lid. Usually, colobomas are located nasally in the upper eyelid and laterally in the lower eyelid.1
Colobomas of the eyelid are rare but can present as a relative emergency in neonate requiring corneal protection, and are frequently associated with systemic and ocular anomalies.2,3 Associated ocular anomalies include dermoid, lipodermoid, keratonus, coloboma of the iris and micro-ophthalmia. Nasopalpebral lipoma–coloboma syndrome is inherited as autosomal dominant trait with full penetrance.4 Colobomas may also occur as part of one of the “first arch” syndromes such as Goldenhar and Treacher Collins syndrome or may be associated with a facial cleft.3 There is also a high incidence of strabismus in the presence of high refractive error or opacities in the ocular media or fibrous bands limiting ocular movements.3 Various factors have been implicated in the pathogenesis of colobomas. Timely and complete epithelial adherence of the lid folds at the ninth week of gestation and its maintenance between the 10th week and the sixth month is required for normal growth of lids and marginal structures.4 Any local factor interfering with this process may lead to palpebral colobomas and maldevelopment of eyelashes, punctae and other adjacent structures. Alternatively, abnormalities in the vascular system and in the neural crest cell development have been implicated in the etiology of the first arch syndromes and failure of fusion in some cases possibly associated with abnormal fibrous bands causes facial clefts.3 Treatment of eyelid colobomas depend primarily on the amount of corneal exposure.3 If corneal integrity is maintained, small lid colobomas may be managed conservatively, with lubricants, air-tight moist chambers and night time patching. This may allow corrective surgery to be delayed until the tissues are more lax and the child is better able to tolerate anesthesia. If the cornea is exposed and the defect is less than 35% of the horizontal fissure, direct closure can achieve excellent cosmetic and functional results. A lateral nthotomy/catholysis may be necessary to facilitate closure of a 35 to 45% defect and to prevent excess tension on the wound. For the colobomas that involve more than 45% of the horizontal length of the eyelid, a two-stage reconstruction may be required.
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