Optic atrophy

Optic atrophy

Optic atrophy is the loss of some or most of the fibers of the optic nerve. In medicine, "atrophy" usually means "shrunken but capable of regrowth", so some argue that "optic atrophy" as a pathological term is somewhat misleading and use "optic neuropathy" instead.

Prognosis

The optic nerve is part of the brain and has no capability for regeneration. Hence, there can be no recovery from optic atrophy and the term may refer to serious or mild, but always irreversible visual loss due to damage to the optic nerve. Three types of degeneration are seen: transsynaptic, anterograde, and retrograde.

Symptoms

There may be symptoms associated with loss of vision (although there may be a particular difficulty with colour vision).

Bilateral Optic Atrophy: Loss of vision and discoloration of discs in both eyes. This is a genetic form and can be inherited.

Causes

Optic atrophy can be congenital or acquired.

Congenital

If congenital, it is usually hereditary with an onset of deterioration in childhood and may be accompanied by nystagmus. Leber's Hereditary Optic Neuropathy, (LHON) or Leber Optic Atrophy is hereditary, but typically has its onset in 20-30 year old males. This is due to a mutation of the mitochondrial genome and hence is passed exclusively through the mothers. Dominant optic atrophy or Kjer's optic neuropathy has autosomal dominant inheritance. It usually presents in early childhood. There are numerous less common genetically related syndromes.

Alternatively, congenital optic atrophy can be caused by a lack of oxygen during pregnancy, labour or in the early days of a child's life. Some drugs taken during pregnancy are also associated with optic atrophy.

Acquired

The acquired type of optic atrophy may be due to blood supply changes in the eye or optic nerve (anterior ischemic optic neuropathy or posterior ischemic optic neuropathy), may be secondary to inflammation or swelling within the optic nerve (optic neuritis), may be a result of pressure against the optic nerve (such as from a tumour), or may be related to metabolic diseases (e.g., diabetes mellitus), trauma, glaucoma, or toxicity (caused by methanol, tobacco, or other poisons). It is also seen in vitamin B12 deficiency and Paget's disease of the bone.

See also

References

External links

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