Optic nerve hypoplasia
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| ICD-10 | Q07.81 |
|---|---|
| ICD-9 | 743.57-743.58 |
Optic nerve hypoplasia is a medical condition that results in underdevelopment of the optic nerves.
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[edit] Development of the optic nerve
During the second month of pregnancy, a structure called the optic stalk develops into a pair of optic nerve bundles. These bundles, which are designed to send signals from the eyes to the occipital lobe of the brain, naturally undergo pruning as the fetus develops. In some individuals, however, either this pruning process is too complete, or the nerves simply fail to develop fully. Such an occurrence causes a congenital condition called optic nerve hypoplasia (ONH).
[edit] Symptoms
Optic nerve hypoplasia can appear in one or both eyes, causing anywhere from a mild to serious visual impairment in the form of decreased visual acuity and visual fields. People with this condition are also more likely to present with photophobia and nystagmus.
Because optic nerve hypoplasia involves the underdevelopment of structures located within the brain, the condition may also be found in conjunction with a constellation of hormonal imbalances and midline brain defects known as septo-optic dysplasia.
[edit] Cause
No one is certain as to what causes optic nerve hypoplasia. The condition is usually not hereditary, but it relatively often occurs in people with albinism, which is hereditary.
There is but a weak correlation between young maternal age, or maternal diabetes, and the occurrence of this condition. It cannot be tied in with any harmful maternal activities, but there is one study[1] that suggests children with FASD, or prenatal alcohol exposure, often have optic nerve hypoplasia.
[edit] Prognosis
Most people with optic nerve hypoplasia - whether they also have septo-optic dysplasia or not - go on to live productive lives.
[edit] References
- ^ Strömland, K., & Pinazo-Durán, M.D. (2002). Ophthalmic involvement in the Fetal Alcohol Syndrome: Clinical and animal model studies. Alcohol and Alcoholism, 37(1), 2-8.
[edit] External links
- Optic Nerve Hypoplasia Facts
- More Optic Nerve Hypoplasia Facts
- FOCUS Families - information, education, and support.
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