Optic nerve hypoplasia is a congenital defect that describes the underdevelopment of the optic nerve during pregnancy. ONH may be the exaggeration of the natural dying back of fibers as the child develops in utero. It can occur in one or both eyes, but more commonly in both.
ONH is not a progressive disease or inherited, and it cannot be cured. It is one of the three most common causes of visual impairment in children.
What causes ONH?
There is no known cause of ONH but it has been associated with maternal alcohol abuse, maternal diabetes, use of anti-epileptic drugs and young maternal age of 20 years or less. However, these incidences account for very few of the total cases.
It appears that all races and socio-economic groups are affected by optic nerve hypoplasia.
Certain characteristics are noted as being associated with the disorder:
Conditions associated with Optic Nerve Hypoplasia
Brain and hormonal abnormalities are common in children suffering with nystagmus (involuntary eye movement) and severe bilateral vision loss. These conditions are less common in those with mild vision loss.
Abnormalities can include encephaloceles (neural tube defect), ventricle anomalies, cerebral atrophy and (rarely) tumors. And hormonal insufficiencies linked to the thyroid, growth hormone, pituitary, adrenal, and anti-diuretic hormone (ADH).
The associated brain anomalies can be identified by an MRI or CT scan. Hormonal insufficiencies will need an examination by a hormonal disorders specialist (pediatric endocrinologist).
Current research has found certain myths that are prevalent in connection with the disorder:
Proposed Teaching Strategies for ONH children