Optic neuritis
The cornea allows light to enter the eye. As light passes through the eye the iris changes shape by expanding and letting more light through or constricting and letting less light through to change pupil size. The lens then changes shape to allow the accurate focusing of light on the retina. Light excites photoreceptors that eventually, through a chemical process, transmit nerve signals through the optic nerve to the brain. The brain processes these nerve impulses into sight.
Also known as: Retro-orbital neuritis
- 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
- 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
- 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
- Body-wide side effects from corticosteroids
- Vision loss
- Your vision decreases
- You develop pain in the eye
- Your symptoms do not improve with treatment
Definition
Optic neuritis is inflammation of the optic nerve. It may cause sudden, reduced vision in the affected eye.
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:
Risk factors are related to the particular cause.
Symptoms
Signs and tests
A complete medical examination can help rule out related diseases. Tests may include the following:
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.
Expectations (prognosis)
People who have optic neuritis without a disease such as multiple sclerosis have a good chance of recovery.
Optic neuritis caused by multiple sclerosis or other autoimmune diseases such as systemic lupus erythematosus has a poorer outlook, although vision in the affected eye may still return to normal.
Complications
About 20% of patients with a first episode of optic neuritis will develop myelin sheath inflammation at other sites or will develop multiple sclerosis.
Calling your health care provider
Call your health care provider immediately if you have a sudden loss of vision in one eye.
If you have optic neuritis, call your health care provider if:
References
Germann CA, Baumann MR, Hamzavi S. Ophthalmic diagnoses in the ED: optic neuritis. Am J Emerg Med. 2007;25:834-837.
Johnston MV. Demyelinating Disorders of the CNS. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th Ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 600.
See also:
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Special Topic
Myelin
Myelin is an insulating layer that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. The purpose of the myelin sheath is to allow rapid and efficient transmission of impulses along the nerve cells. If the myelin is damaged, the impulses ...
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Disease
Autoimmune disorders
An autoimmune disorder is a condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue. There are more than 80 different types of autoimmune disorders. See also:
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Disease
Multiple sclerosis
Multiple sclerosis is an that affects the brain and spinal cord ().
- Review date:
- August 29, 2009
- Reviewed by:
- Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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