Congenital Anomalies of the Optic Nerve

Le résumé fourni par la source

Abstract This chapter traces the normal development of the optic nerve throughout gestation before discussing aplasia of the optic nerve, a rare condition in which the optic nerve fails to develop, and optic nerve hypoplasia, a congenital, nonprogressive developmental abnormality characterized by reduced numbers of retinal ganglion cells and corresponding defects in the nerve fiber layer of the retina. Other conditions covered are duplication of the optic nerve, an extremely rare condition characterized by the presence of two separate nerves exiting from the globe, pseudo-duplication of the optic nerve, a developmental abnormality in which retinal vasculature appears to emerge from a second, often slightly cupped or excavated, location in the retina, and megalopapilla, an abnormally large optic disc with no anatomic defects. Cavitary malformations of the optic nerve, broadly referred to as “optic nerve coloboma” are also covered, including uveal coloboma; morning glory disc anomaly; PAX2-related congenital optic nerve anomalies (papillorenal syndrome); peripapillary staphyloma, a rare, non-progressive, congenital abnormality in which a relatively normal appearing optic nerve head sits at the base of a posterior pole excavation; and optic pits, excavations of variable color, depth, and location in the disc substance. Congenital tilted disc and congenital optic disc pigmentation are discussed, as are Bergmeister’s papilla, a benign anomaly that describes an optic nerve head with veil-like remnants of the primary vitreous in its center or covering it, and myelinated fibers. Finally, the chapter covers congenital vascular anomalies: prepapillary vascular loops, cilioretinal arteries, optociliary veins, and optic disc drusen.

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