Optic Neuritis (ON) Symptoms & Causes

What is Optic Neuritis (ON)?

Optic neuritis (ON) involves an attack of inflammation (swelling) in your optic nerve, which sends information from your eye to your brain about what you are seeing. In ON, there is damage to myelin, the protective covering of your nerve fibers. Myelin is also called white matter due to its color. Because ON affects myelin, it is a type of "demyelinating" disorder.

What are the symptoms of ON?

The symptoms of ON can affect one or both eyes. They include:

  • blurred vision
  • loss of color vision
  • complete loss of vision
  • eye pain

What causes ON?

ON is an "autoimmune" condition that often follows an infection such as a cold. Your immune system protects your body from things like bacteria and viruses, but autoimmune diseases confuse your body's immune system. Instead of fighting against bacteria or viruses, it attacks your healthy cells and tissue. In ON, your immune system reacts against your optic nerve. Autoimmunity is not contagious, but it may be genetic (inherited from parents).

ON may also follow a vaccination, although this is rare. In some cases of ON, a specific trigger/cause cannot be identified.