Optic neuritis Health Article

Definition

Optic neuritis is inflammation of the optic nerve. It may cause sudden, reduced vision in the affected eye.

Alternative Names

Retro-orbital neuritis

Causes, incidence, and risk factors

The cause of optic neuritis is unknown.

Sudden inflammation of the nerve connecting the eye and the brain (optic nerve) can injure the insulation (myelin sheath) surrounding each nerve fiber, causing the nerve to swell.

Causes of the inflammation can include:

• Autoimmune diseases (systemic lupus erythematosus, sarcoidosis, Behcet disease, autoimmune optic neuritis)
• Infections (tuberculosis, syphilis, Lyme disease, meningitis, viral encephalitis, and post-infectious measles, rubella, chickenpox, herpes zoster, mumps, and Mycoplasma pneumonia or other common upper respiratory tract infections)
• Multiple sclerosis (most often in adults, but also in children)
• Toxicity from drugs such as methanol or ethambutol
• Vitamin B-12 deficiency

Risk factors are related to the particular cause.

Symptoms

• Loss of vision in one eye, over the course of an hour or a few hours
• Changes in the way the pupil reacts to bright light
• Loss of color vision
• Pain when you move the eye

Signs and tests

A complete medical examination can help rule out related diseases. Tests may include the following:

• Color vision testing
• MRI of the brain including special images of the optic nerve
• Visual acuity testing
• Visualization of the optic disc by indirect ophthalmoscopy

Treatment

Vision often returns to normal within 2 - 3 weeks with no treatment.

Corticosteroids given through a vein (IV) may speed up recovery. Higher doses should be used cautiously, as they can have serious side effects.

Further tests may be needed to determine the cause of the neuritis. The condition causing the problem can then be treated.