MOG and optic neuritis: Relevant articles were identified by a search of of PubMed, by inputting the terms “optic neuritis” AND “pain”, “optic neuritis” AND “classification”, “multiple sclerosis” AND “pain”, “neuromyelitis optica” AND “pain”, “myelin oligodendrocyte glycoprotein AND “pain”, “pain with eye movement” and “treatment” AND “pain related to ON”.