Among the various causes of retrobulbar neuritis, demyelinating diseases of the brain and visual pathways play a most significant role. Prominent in the group of diseases classified as "encephalomyelopathies" is multiple sclerosis, a disease of unknown causation. In contrast to other causes of retrobulbar neuritis, it is characterized by recurrent episodes of symptoms and by remarkable variation in the intensity of disturbance of function in relation to the rapidity of onset of symptoms and to the degree of recovery from a number of episodes. Between attacks, the symptoms of which may be constitutional or local, the patient may experience no general, local or permanent effects. In the great majority of cases, multiple sclerosis begins with comparatively mild symptoms, from which recovery usually is complete. Subsequent attacks may not occur for a number of years.
Alpers1 stated :
The history of vertiginous attacks over widely scattered periods with what appear to