What is optic neuritis?

Optic neuritis (ON) is an inflammation of the optic nerve, a bundle of fibers that transmits visual information from your eye to your brain. Symptoms of ON are varied, often including pain behind the eye and different degrees of vision loss. People with ON may experience blurry vision, blind spots, a graying out of vision, or dull colors. ON can, but does not always, result in temporary blindness and usually affects only one eye at a time. ON may be accompanied by flashes of light or new floaters which should be reported to your eye doctor and/or neurologist.

What causes optic neuritis?

Common causes of optic neuritis include demyelinating diseases, such as multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD, formerly known as neuromyelitis optica or Devic’s disease). In MS and NMOSD, the immune system attacks the myelin surrounding nerve fibers of the brain, optic nerves, or spinal cord resulting in inflammation and/or lesions that disrupt nerve signals to and from the brain. If NMOSD is suspected, a blood test can help distinguish it from MS and facilitate diagnosis.

Other causes of optic neuritis may include bacterial or viral infections (e.g., Lyme disease, cat-scratch fever, syphilis, measles, mumps, herpes), other autoimmune diseases (e.g., sarcoidosis, lupus), or drug side-effects (e.g., quinine, some antibiotics), according to the Mayo Clinic.

When I had the blinding case of optic neuritis in 2000, the results of my MRI showed inflammation of the optic nerve but no lesions.

I was not diagnosed with “post-infectious optic neuritis.” I had had a severe cold during the prior weeks. The MRI helped to eliminate the other potential diagnosis suggested, which was brain tumor. Fortunately, I did not have a brain tumor.

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MS Signs & Symptoms: Optic Neuritis