Causes and Risks: The cause of optic neuritis is unknown. Sudden inflammation of the optic nerve leads to swelling and destruction of its myelin sheath. The inflammation may be the result of a viral infection or autoimmune diseases, such as multiple sclerosis. Risk factors are related to the possible causes. The actual incidence is not reported.

Prevention: Most cases are not preventable.

Symptoms:

• Acute loss of vision in one eye
• Loss of color vision
• Pain on movement of the eye
• Decreased constriction of the pupil of the affected eye in bright light

Signs and Tests:

A complete medical examination is indicated to rule out associated diseases.

Tests may include:

• Visual acuity
• Color vision testing
• Visualization of the optic disc by indirect ophthalmoscopy
• MRI (magnetic resonance imaging) of the brain to test for multiple sclerosis

Treatment: Visual acuity may return to normal within 2 to 3 weeks with no treatment. Intravenous corticosteroid therapy may accelerate visual recovery, but may be associated with systemic side effects. Oral corticosteroid therapy may increase the risk of recurrence and is no longer used for initial therapy.  It may be used after initial intravenous corticosteroid therapy.  Further diagnostic evaluation may be necessary.

Prognosis: Optic neuritis with no underlying systemic disease has a good prognosis for recovery.  Optic neuritis resulting from multiple sclerosis, or other autoimmune disease such as systemic lupus erythematosis is associated with a poorer prognosis.

Complications:

• Systemic side effects of therapy
• Vision loss
• About 20% of patients with a first episode of optic neuritis will develop multiple sclerosis

Call your health care provider immediately if sudden loss of vision in one eye occurs.

If you have optic neuritis, call your health care provider if vision decreases, pain in the eye develops, or if symptoms do not improve with treatment.