Definition

The optic nerve allows you to see by carrying images from your eye to your brain. Optic neuritis involves inflammation of the optic nerve. This may cause sudden decrease or loss of vision. It is a serious condition that requires immediate care from your doctor.

The Optic Nerve

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Causes

The cause of optic neuritis is often unknown. Known causes of the diseases include:

• An attack on the optic nerve by a viral infection or by the body's own immune system—This may be associated with the autoimmune disorders, such as:
  • multiple sclerosis
  • Neuromyelitis optica
• Exposure to toxic substances (eg, lead, certain nutritional deficiencies)—This can be associated with optic neuropathy (injury to the optic nerve).

Risk Factors

The following factors increase your chance of developing optic neuritis. If you have any of these risk factors, tell your doctor:

• Personal or family history of multiple sclerosis or other autoimmune disorders—Autoimmune diseases, in general, are more common in women of child-bearing age.
• Previous history of optic neuritis
• Previous history of transverse myelitis (inflammation of the spinal cord)

Symptoms

Symptoms of optic neuritis include:

• Sudden decrease in vision—Patients may describe this as blurred, dark, or dim vision, or as loss of vision in the center of, part of, or all of the visual field. In mild cases, it may look like “the lights are turned down.”
• Abnormal color vision (dull and faded colors)
• Pain in or around the eye (often made worse by movement of the eye)

Eye pain will often go away, usually within a few days. Vision problems will improve in over 90% of patients. Although, some may be left with blurred, dark, dim, distorted vision, or complete visual loss. Vision improvement usually takes place over several weeks or months.

Diagnosis

Optic neuritis may be difficult to diagnose, as your eye may look perfectly normal. Your doctor will ask about your symptoms and medical history. She will also do a physical examination, including a neurologic examination. You may be referred to an ophthalmologist or neurologist. Tests may include:

• Tests of color vision, side vision, visual acuity, and the reaction of the pupil to light
• Dilated eye examination—to view the back of the eye (retina) with an instrument called an ophthalmoscope
• MRI scan—a test that uses magnetic waves to make pictures of structures inside the body; may be done to look for certain medical conditions
• Lumbar puncture—a sample of the cerebrospinal fluid is taken from the lower back; may be done to look for autoimmune causes
• Blood tests—to look for potential causes
• Visual evoked potential test— may be done to evaluate how well the optic nerves are conducting information back to the brain
• Somatosensory evoked potentials test—may be done to evaluate for any spinal cord problems, which may be associated with optic neuritis

Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include:

• Steroid medicine to reduce inflammation of the optic nerve
• Medicine to treat the cause of optic neuritis
• Observation

Prevention

There is no known way to prevent a first episode of optic neuritis. The chance of having a repeat episode may be reduced if the first episode is treated with a steroid or other medicine. It is very important to see a doctor right away if you develop pain or decreased vision.