Optic Neuritis

  • Medical Author:
    Andrew A. Dahl, MD, FACS

    Andrew A. Dahl, MD, is a board-certified ophthalmologist. Dr. Dahl's educational background includes a BA with Honors and Distinction from Wesleyan University, Middletown, CT, and an MD from Cornell University, where he was selected for Alpha Omega Alpha, the national medical honor society. He had an internal medical internship at the New York Hospital/Cornell Medical Center.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Optic neuritis facts

  • Optic neuritis is an inflammation of the optic nerve.
  • Optic neuritis most commonly affects young adults in one eye.
  • Optic neuritis is frequently associated with multiple sclerosis. Other causes include infections, autoimmune disease, and injury to the optic nerve.
  • The symptoms of optic neuritis include vision loss, reduced color vision, and pain on movement of the eye with recovery over weeks to a month, in most cases.
  • The diagnosis is made on the basis of the patient history and an examination by an ophthalmologist. An MRI is important to look for lesions that indicate the patient may develop multiple sclerosis. Blood tests may be indicated.
  • High-dose IV corticosteroids speed up recovery, but appear to have no effect on the long-term outcome.

What is optic neuritis?

Optic neuritis is an inflammation that affects the myelin lining of the optic nerve, which transmits visual stimuli to the brain. The optic nerve is actually a nerve tract of axons that originate in the ganglion cells of the retina in the back of the eye. Nerve tracts are the information pathways in the brain. The "optic nerves" are the only nerve tracts not located entirely within the brain. The optic nerves carry visual information from the retina to the area of the brain that recognizes vision (the occipital cortex).

Optic neuritis can occur in children or adults and may involve either one or both optic nerves. Optic neuritis typically affects young adults ranging from 20 to 40 years of age. There is a strong female predominance. The annual incidence is approximately 6.4/100,000.

Optic Neuritis Symptoms

Vision loss symptoms

Loss of vision can occur suddenly or develop gradually over time. Vision loss may be complete (involving both eyes) or partial, involving only one eye or even certain parts of the visual field. Vision loss is different from blindness that was present at birth, and this article is concerned with causes of vision loss in an individual who previously had normal vision. Vision loss can also be considered as loss of sight that cannot be corrected to a normal level with eyeglasses. The causes of loss of vision are extremely varied and range from conditions affecting the eyes to conditions affecting the visual processing centers in the brain. Impaired vision becomes more common with age. Common causes of vision loss in the elderly include diabetic retinopathy, glaucoma, age-related macular degeneration, and cataracts.

What causes optic neuritis?

The precise cause of optic neuritis is unknown, but it is thought to be a type of autoimmune disorder. The immune system is generally used by the body to fight infection by creating a reaction that combats bacteria, viruses, fungi, and other foreign proteins. In autoimmune diseases, this reaction is mistakenly directed against a normal part of the body, creating inflammation and potential damage. In the case of optic neuritis, the optic nerve becomes swollen and its function is impaired. Inflammation and destruction of the protective myelin sheath that coats and insulates the optic nerve, plus direct damage to the nerve axons results in loss of vision, which may be temporary or permanent.

Optic neuritis is frequently an indication of multiple sclerosis (MS), a disease in which the immune system attacks the myelin sheath covering nerve fibers in the brain and spinal cord, resulting in inflammation and nerve damage. Optic neuritis typically resolves initially but often recurs.

In 15%-20% of people who eventually develop multiple sclerosis, optic neuritis is their first symptom. The risk of developing multiple sclerosis following one episode of optic neuritis is approximately 50% within 15 years of any first episode of optic neuritis. Various studies have shown that approximately 50% of patients who have optic neuritis for the first time will have MRI brain and/or spinal cord abnormalities consistent with MS at the time of the initial optic neuritis.

Neuromyelitis optica is another autoimmune condition in which demyelination occurs both in the spinal cord and both optic nerves but often sparing the brain. In this infrequent condition, the patient can experience weakness or paralysis in the limbs and/or bladder and bowel dysfunction, as well as loss of vision.

Approximately one-half of initial cases of optic neuritis are presumed to be an inflammatory reaction developing one week to one month following an upper-respiratory viral infection.

There are a variety of conditions that can affect the optic nerve, causing symptoms similar to optic neuritis. These include various optic neuropathies due to infection, trauma, hereditary conditions, toxic or nutritional problems, compressive lesions of the optic nerves, and vascular diseases, including arteritic optic neuropathy, diabetes, and glaucoma. Treatment of these optic neuropathies is directed at the underlying disease.

What are optic neuritis risk factors?

Optic neuritis risk factors include trauma, hereditary conditions, toxic or nutritional problems, compressive lesions of the optic nerves, and vascular diseases, including arteritic optic neuropathy, diabetes, and glaucoma.

What are symptoms of optic neuritis?

The major symptom of optic neuritis is vision loss, usually in one eye, often developing within hours to a couple of days and peaking in one to two weeks. It may vary from a small area of blurring to complete blindness. Affected individuals may also notice distorted vision, inability to distinguish certain colors, loss of contrast, and washed-out or less vivid vision than normal. Symptoms may be worsened by heat or exercise. Vision loss is usually temporary, but it may be permanent in some cases.

Most people who develop optic neuritis experience eye pain that is worsened by eye movement. The intensity of the pain usually follows the course of the vision loss, decreasing and disappearing within one to four weeks.

Because optic neuritis usually affects one eye, patients may be unaware of subtle visual loss or changes in the color vision until they or doctors close or cover the healthy eye.

What are signs of optic neuritis?

The most characteristic findings on examination include reduced visual acuity (typically 20/25 to 20/200), a measurable change in peripheral vision, decreased perception of brightness in the affected eye, and loss of color vision out of proportion to the loss of visual acuity. A disturbance in reaction of the pupil (afferent pupillary defect or APD) is usually detectable if the other eye is either unaffected or involved to a lesser degree.

The optic nerve head can easily be visualized with an ophthalmoscope. In one-third of the cases, there is visible swelling of the optic nerve head, and there may be enlargement of the blood vessels around the nerve. This condition is called papillitis. In about two-thirds of patients, the inflammation is entirely behind the eye (retrobulbar), causing no visible changes when the physician examines the optic nerve with an ophthalmoscope. This is called retrobulbar neuritis.

What types of doctors treat optic neuritis?

An ophthalmologist is a medical doctor who specializes in the diagnosis and treatment of eye disease. Ophthalmologists diagnose and treat optic neuritis, often in conjunction with a neurologist or family physician. Other specialists are involved based on any underlying diseases.

How do health-care professionals diagnose optic neuritis?

Optic neuritis is suspected based on the characteristic history of eye pain and vision loss. The standard exam includes visual acuity, pupillary reduction, visual field evaluation, color vision testing, and visualization of the optic disc by direct and indirect ophthalmoscopy.

A person experiencing a first episode of optic neuritis should undergo an MRI of the brain to detect central nervous system lesions associated with MS. The MRI may also show an enlarged optic nerve or inflamed optic nerve sheath.

Visual symptoms usually progress for the first few weeks and then start to improve within the first month. If the course of recovery is not typical, further testing can be performed to look for more unusual causes of optic neuritis/neuropathy.

What is the treatment for optic neuritis?

If a definite cause (such as infection or underlying other disease) is determined, appropriate therapy for that cause is instituted.

The Optic Neuritis Treatment Trial, a multicenter randomized trial with 15 years of follow-up, showed that oral corticosteroids (prednisone) had no benefit on recovery to normal visual acuity. High-dose intravenous steroids, which involve some risks and can have significant side effects in some patients, including elevated blood sugar, depression, and insomnia. In the trial, high-dose intravenous steroids did speed up the initial recovery of vision in the acute phase. However, there was no conclusive evidence that intravenous steroids had any long-term benefit on visual acuity, visual field, or contrast sensitivity five years later.

Although there is no evidence that the use of oral nonsteroidal anti-inflammatory drugs (NSAIDs) have an effect on ultimate visual outcomes, they are effective in decreasing the pain on eye movement often associated with optic neuritis.

Good nutrition and hydration, avoidance of tobacco, and refraining from vigorous exercise or over-heating is often recommended during the acute phase of optic neuritis.

What is the prognosis for optic neuritis?

The prognosis depends on the underlying cause. Most episodes resolve spontaneously, with return of vision in two weeks to three months. About 90% of people with optic neuritis will recover most of their vision within six months of onset. However, about 14% will have a recurrence of optic neuritis in the affected eye, and 12% will develop optic neuritis in the other eye within 10 years. If the patient has one or more abnormal lesions on the MRI, the risk of MS within 15 years is 72%.

Is it possible to prevent optic neuritis?

Since almost 50% of optic neuritis is likely a result of a post-viral immune reaction, minimizing your risk of acquiring a viral respiratory infection decreases your risk of optic neuritis. It is impossible to totally avoid exposure to respiratory viruses, but research has shown that frequent hand-washing and attempting to not touch one's face without first washing one's hands decreases the incidence of the common cold. Teaching children to cover their mouths and noses when sneezing and instructing them on personal hygiene can also decrease the chances of upper respiratory virus spreading within families.

In patients with recurrent optic neuritis secondary to multiple sclerosis, there are approved disease-modifying agents that reduce disease activity and disease progression for many people with relapsing forms of MS, including relapsing-remitting MS, as well as progressive forms of MS in those people who experience relapses. These include injectable forms of interferon beta, glatiramer acetate, and the biologic monoclonal antibody, daclizumab. Oral medications include teriflunomide, fingolimod, and dimethyl fumarate.

Relapses of multiple sclerosis are sometimes treated with a three- to five-day course of intravenous high-dose corticosteroids. Similar to the use of this regimen in treating acute optic neuritis, intravenous corticosteroids will often end the relapse more rapidly but does not have any effect on the long-term outcome of the disease.

Where can I find more information on optic neuritis?

American Academy of Ophthalmology
http://www.aao.org

REFERENCE:

Lorefice, Lorena, et al. "Monoclonal Antibodies: A Target Therapy for Multiple Sclerosis." Inflammation & Allergy-Drug Targets (Formerly Current Drug Targets -- Inflammation & Allergy) 13.2 May 2014: 134-143(10).

Last Editorial Review: 8/22/2016

Reviewed on 8/22/2016
References
REFERENCE:

Lorefice, Lorena, et al. "Monoclonal Antibodies: A Target Therapy for Multiple Sclerosis." Inflammation & Allergy-Drug Targets (Formerly Current Drug Targets -- Inflammation & Allergy) 13.2 May 2014: 134-143(10).

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