2020–2021 BCSC Basic and Clinical Science Course™
7 Oculofacial Plastic and Orbital Surgery
Part II: Periocular Soft Tissues
Chapter 10: Classification of Eyelid Disorders
A coloboma is an embryologic cleft that is usually an isolated anomaly when it occurs in the medial upper eyelid. A true coloboma includes a defect in the eyelid margin (Fig 10-12).
Figure 10-10 Congenital tarsal kink.
(Courtesy of Don O. Kikkawa, MD.)
Figure 10-10 Congenital distichiasis.
(Courtesy of Jill Foster, MD.)
Figure 10-12 True coloboma of the upper eyelid.
(Courtesy of Cat N. Burkat, MD.)
When located in the lower eyelid, however, a coloboma is frequently associated with other congenital conditions such as facial clefts (eg, Goldenhar syndrome) and lacrimal deformities.
Full-thickness defects affecting up to one-third of the eyelid can usually be repaired by creating raw vertical margins and sliding flaps along the eyelid crease. A lateral cantholysis may provide additional horizontal relaxation. Almost all large defects can be repaired with use of a variation of the lateral canthal semicircular flap technique (see Chapter 11 in this volume). Because of the risk of amblyopia, eyelid-sharing procedures that occlude the visual axis are avoided unless no other reconstructive options are possible.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.