Inclusion Criteria:  Both genres Age between 18 and 85 years old. Optic neuritis diagnosis ( relative afferent pupillary defect, acquired dyschromatopsia, low vision, prechiasmatic campimetric defect) 1 month after symptoms started If is a bilateral simultaneous optic neuritis the eye with the worst vision will be included. if is a bilateral sequential optic neuritis the eye with lees 1 month evolution will be included.  Exclusion Criteria:  Visual field better than 20/60 at the beginning of the study. History of optic neuritis in the eye under study. History of additional ophthalmological or neurological pathology that has caused visual loss in the eye under study. History of previous treatment with intravenous methylprednisolone since the onset of symptoms. History of high myopia.