What is optic neuritis?

See below. Optic neuritis is due to inflammation and damage of the insulation material around the nerve behind the eye ball (optic nerve). This results in variable loss of vision in one eye, pain with eye movement, for weeks to months followed by recovery. It can be the first event of MS or may be a one time event. Brain MRI taken at the time of optic neuritis can be valuable to gauge risk for future ms.