Optic Neuritis

Optic neuritis refers to swelling or inflammation of the optic nerve. The optic nerve allows you to see by carrying images from your retina to your brain. The optic nerve is like a cable of electrical wires or nerve fibers. Each wire carries a part of the visual information to the brain. If some or all of the nerve fibers become inflamed and do not function properly, vision becomes blurred. With optic neuritis, the optic nerve becomes swollen and the nerve fibers do not work properly. Vision can range from near normal to very poor depending on the number of inflamed nerve fibers.

Various diseases and conditions may cause optic neuritis. In many cases, however, the cause of optic neuritis is not known. It is often associated with diseases causing demyelination (a loss of the protective myelin layer of the the nerve) of the optic nerve. Multiple sclerosis (MS) is the disease most often associated with optic neuritis. It is not uncommon to have an episode of optic neuritis prior to being diagnosed with MS. In fact, optic neuritis is often the initial sign of MS. Some people, especially children, develop optic neuritis following a viral illness such as mumps, measles or a cold. In others, optic neuritis may occur as a sign of a neurologic disease affecting nerves in various parts of the body.

The following symptoms of optic neuritis may not occur in all cases; however, they are the most common problems associated with the condition.

• Pain behind the eye with eye movement (more than 90% of patients)
• Tender, sore eye
• Mild to severe decrease in central vision, or central blind spot
• Dull, dim vision (as if the lights were turned down)
• Blurred or decreased vision in one or both eyes (especially after exercising or taking a hot bath)
• Reduced color perception
• Decreased peripheral vision
• Fever
• Headache
• Nausea

The symptoms described above may not necessarily mean that you have optic neuritis. However, if you experience one or more of these symptoms, contact your eye doctor for a complete exam.

Fortunately, most people recover normal vision without any treatment of optic neuritis. For some people with significant vision loss, treatment with high doses of corticosteroids given intravenously may hasten visual recovery. Optic neuritis characteristically improves over a period of days to weeks. For some, a complete recovery may take months

Since the Optic Neuritis Treatment Trial (ONTT), doctors have discovered that treating patients with intravenous steroid medication (but not oral steroids) reduces the risk of developing MS later on. This finding is very significant since approximately 50% of those who experience an initial occurrence of optic neuritis will develop MS. While this treatment has little if any impact on vision, it is important for overall health.