Optic nerve hypoplasia.

Optic nerve hypoplasia is now recognized as a common developmental anomaly of the optic nerve. It has a large clinical spectrum of findings, but is most often associated with impaired vision and a small optic disc. Additional findings which aid in the diagnosis include a Marcus Gunn pupil, a double peripapillary ring, and pathological thinness of the retinal nerve fiber layer. Bilateral optic nerve hypoplasia may be a clue to midline developmental anomalies of the brain. Our case of optic nerve hypoplasia illustrates its variability of presentation and underscores the importance in investigating every case of unexplained decreased vision.