The initial phase of optic neuromyelitis optica can manifest as either simple optic neuritis or myelitis optica, or both, or both. Optic neuromyelitis optica has a rapid onset and progression, with symptoms often worsening or peaking within a few days in most patients. 80%-90% of patients have a recurrent course. 60% of patients have a recurrence within 1 year and 90% within 3 years. The prognosis for optic neuromyelitis optica is poor, with about half of the patients blind in at least one eye within 5 years or unable to walk independently and disabled for life. 20% of patients die of respiratory failure due to cervical myelitis. The onset of multiple sclerosis is usually mild, and the initial onset is often not taken seriously as the disease recurs, gradually worsening and eventually leading to permanent disability. Optic neuromyelitis optica is rarely seen as a secondary progressive stage of multiple sclerosis, and optic neuromyelitis optica often coexists with other autoimmune diseases such as thyroiditis, dry syndrome, and systemic lupus erythematosus. Although there is a lack of large-scale multicenter double-blind studies, clinical observations and experience suggest that immunosuppressive agents should be chosen for the treatment of optic neuromyelitis optica, while immunomodulators can be used for the treatment of multiple sclerosis.