Science Fair Project Encyclopedia
Optic nerve hypoplasia
Optic nerve hypoplasia is a medical condition that results in underdevelopment of the optic nerves.
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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).
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.
Cause
No one is certain as to what causes optic nerve hypoplasia. The condition is not hereditary, and nor can it be tied in with any harmful maternal activities.
There is but a weak correlation between young maternal age, or maternal diabetes, and the occurrence of this condition.
Effect
Most people with optic nerve hypoplasia - whether they also have septo-optic dysplasia or not - go on to live productive lives.
External links
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