2020–2021 BCSC Basic and Clinical Science Course™
6 Pediatric Ophthalmology and Strabismus
Part II: Pediatric Ophthalmology
Chapter 21: Disorders of the Anterior Segment
Congenital and Developmental Anomalies of the Globe
Microphthalmia, Anophthalmia, and Coloboma
Microphthalmia, anophthalmia, and coloboma (MAC) is a spectrum that may be isolated or syndromic. It has been associated with mutations in numerous genes, including CHX10, MAF, PAX6, PAX2, RAX, SHH, SIX3, and SOX2.
Microphthalmia is a small, disorganized globe that can be associated with cystic outpouching of the posteroinferior sclera.
Anophthalmia is absence of any ocular globe tissue (see Chapter 18). It is very rare; usually, when anophthalmia is clinically suspected, the child actually has severe microphthalmia.
Coloboma is the most common and least severe manifestation of the MAC spectrum. It is typically an inferonasal gap in the iris or retina. Coloboma results from failure of the embryonic fissure to close in the fifth week of gestation.
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.