There are numerous developmental anomalies of the optic nerve, such as optic nerve hypoplasia, optic nerve colobomas, optic (nerve head) pits, morning glory disc anomaly, and Bergmeister papilla. Only those entities that have been well characterized histologically are discussed in this section. See BCSC Section 5, Neuro-Ophthalmology, and Section 6, Pediatric Ophthalmology and Strabismus, for additional discussion of developmental anomalies of the eye, including the optic nerve.
Colobomas of the optic nerve result from defective closure of the embryonic fissure. They are often inferonasal and may be associated with colobomatous defects of the retina and choroid, ciliary body, and iris (Fig 15-3A). Histologically, there is a large defect in the optic nerve, and atrophic, gliotic retina lines the defect. The sclera is commonly ectatic and bowed posteriorly (Fig 15-3B). The defect wall may contain adipose tissue and even smooth muscle.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.