Isolated optic nerve hypoplasia

What it is

A rare developmental defect during embryogenesis characterized by underdevelopment of the optic nerve with a subnormal number of optic nerve axons. The condition may be unilateral or bilateral and can occur as an isolated defect or accompany other ocular or cerebral abnormalities. Funduscopic examination reveals a small optic disc, often associated with the ''double-ring'' sign, a ring of hypo- or hyperpigmentation surrounding the disc. Clinically, vision may be severely impaired or remain unaffected.

Key facts

Prevalence

<1 / 1 000 000

Inheritance

Autosomal dominant, Autosomal recessive

Classified as

Morphological anomaly

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references