Optic neuromyelitis optica (neuIOmyeiitiS Optica) is an idiopathic inflammatory demyelinating disease typically characterized by recurrent episodes of disease with lesions mainly invading the optic nerve and spinal cord, and rarely the brain in the early stages. Because of the overlap of manifestations with multiple sclerosis, it is difficult to distinguish the two clinically, and for many years many scholars have regarded it as a subtype or variant of multiple sclerosis, but recent research findings have challenged the traditional concept that optic neuromyelitis optica is a separate disease from multiple sclerosis.