Retrobulbar neuritis is a form of optic neuritis in which the optic nerve, which is at the back of the eye, becomes inflamed. The inflamed area is between the back of the eye and the brain. The optic nerve contains fibers that carry visual information from the nerve cells in the retina to the nerve cells in the brain. When these fibers become inflamed, visual signaling to the brain becomes disrupted, and vision is impaired.
Retrobulbar neuritis can be caused by a variety of conditions, including:
- Infections such as meningitis, syphilis and various viral illnesses
- Multiple sclerosis
- Exposure to certain chemicals or drugs
- Allergic reactions
However, in many cases, the cause is unknown. Vision loss can be minimal or the disease can result in complete blindness.
The average age of people who develop optic neuritis is 32. Most are female, and the vast majority also have pain when they move their eyes. Retrobulbar neuritis often is an early sign that someone has multiple sclerosis. Between 20% and 40% of the 25,000 people who develop optic neuritis in the United States each year will develop multiple sclerosis within 10 years.
Symptoms usually worsen for two weeks and then stabilize. However, the course of the illness varies greatly. Most cases show some improvement over time, although complete recovery is rare. Optic neuritis usually affects only one eye, but both eyes may be affected. Common symptoms include:
- Blurred or dimmed vision
- A blind spot at or near the center of vision
- Color "wash-out" so that colors are less rich
- Pain with eye movement
- Tenderness of the eye to touch or pressure
- Complete blindness in the affected eye
A doctor will use an ophthalmoscope to examine the back of the eye, particularly the optic disc. This is where the optic nerve fibers concentrate before exiting the eye to extend back toward the brain. In the early stages of retrobulbar neuritis, the optic disk appears normal. Later, it may become pale.
The pupil normally becomes smaller (constricts) in response to light. In retrobulbar neuritis, this response often is reduced in the affected eye. The doctor also will test your visual acuity, which frequently is impaired in the affected eye. The doctor will test your side(peripheral)vision because, in many cases of retrobulbar neuritis, a scotoma, a blind or dark spot in the visual field, may be detected. The doctor also may search for associated conditions, such as infection or multiple sclerosis, after a detailed discussion about other symptoms and a complete physical examination.
How long this condition lasts depends on the cause, and in some people, optic neuritis continues to return. In some cases, if the optic nerve is permanently damaged, it can lead to blindness.
Because the underlying cause of most cases of retrobulbar neuritis is unknown, there is usually no way to prevent it. Practicing safe sex to avoid certian infections such as syphilis and being cautious around chemicals and toxins is always wise.
Many cases improve without treatment. Sometimes, a corticosteroid medication, such as intravenous methylprednisolone, is used to treat retrobulbar neuritis. The type of therapy depends on the suspected cause of the problem. For example, if an MRI shows abnormalities suggestive of multiple sclerosis in the brain or spinal cord, treatment with interferon or glatiramer acetate (Copaxone) may lessen the likelihood of repeated attacks of neuritis and may also lessen the chances of progression to definite multiple sclerosis.
Call a doctor if you experience any vision changes, either suddenly or over time. Pain in or around the eye, with or without vision loss, also should receive prompt medical attention.
The outlook depends on the cause. Cases in which there is no obvious cause or in which the cause is multiple sclerosis often improve after two weeks, but the vision may never completely return to normal.
Retrobulbar neuritis may return, and many people with retrobulbar neuritis eventually develop multiple sclerosis. If an MRI image of the brain is abnormal in a manner typical of multiple sclerosis at the time of retrobulbar neuritis, clinically obvious multiple sclerosis is much more likely than if the MRI is normal.
National Eye Institute
2020 Vision Place
Bethesda, MD 20892-3655
American Academy of Ophthalmology
P.O. Box 7424
San Francisco, CA 94120-7424