[Retrobulbar optic nevritis and chicken pox: a case report in a child].

We report here the case of a three-year-old boy presenting with an optic neuritis during the invasive phase of a chicken pox. This clinical, infrequent picture, can be directly due to the virus or be secondary to an auto-immune mechanism. The examination of the ocular fundus, the profile of the spinal fluid, the MRI and the measure of visual evoked potential allow to reach diagnosis and to identify the type of lesion. There is no consensus on the treatment of this optic neuritis and the current attitude is therapeutic abstention because of a rapid spontaneous improvement. Cerebellitis, meningitis can also be seen during chicken pox. Their evolution is quickly favorable, not requiring additional exam. Encephalitis can result from an auto-immune lesion of the white matter and require then the use of corticoids with antiviral drugs.