2020–2021 BCSC Basic and Clinical Science Course™
11 Lens and Cataract
Chapter 4: Embryology and Developmental Defects
Congenital Anomalies and Abnormalities
A lens coloboma is an anomaly of lens shape (Fig 4-5). Primary coloboma is a wedgeshaped defect or indentation of the lens periphery that occurs as an isolated anomaly. Secondary coloboma is a flattening or indentation of the lens periphery caused by the lack of ciliary body or zonular development. Lens colobomas are typically located inferonasally and may be associated with colobomas of the iris, optic nerve, or retina. Cortical lens opacification or thickening of the lens capsule may appear adjacent to the coloboma. The zonular attachments in the region of the coloboma are usually weakened or absent.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.