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

The Optic Nerve

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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 autoimmune disorders, such as:
  • Multiple sclerosis (MS)
  • Neuromyelitis optica (NMO, Devic’s disease)
• Exposure to toxic substances. This can be associated with optic neuropathy (injury to the optic nerve).
• Some medicines

Risk factors that increase your chanced of developing optic neuritis include:

• Personal or family history of multiple sclerosis or other autoimmune disorders—Autoimmune diseases 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 of optic neuritis include:

• Sudden decrease in vision—blurred, dark, or dim vision, or 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 with eye movement)

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

Optic neuritis may be difficult to diagnose. Your eye may look perfectly normal. Your doctor will ask about your symptoms and medical history. A physical exam will be done. It will include a neurologic examination. You may be referred to an ophthalmologist (eye specialist) or neurologist (brain and nervous system specialist).

Your doctor may need to test your eye function. This can be done with:

• Tests of color vision, side vision, visual acuity, and the reaction of the pupil to light
• Dilated eye examination
• Visual evoked potential test
• Optical coherence tomography (OCT)

Your doctor may need to test your body fluids. This can be done with:

• Blood tests
• Lumbar puncture

Your doctor may need pictures of your body structures. This can be done with an MRI scan

Your doctor may also need to evaluate you for spinal cord problems. This can be done with a somatosensory evoked potentials test.

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

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

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