Neuromyelitis optica (NMO) is an autoimmune, inflammatory, demyelinating disorder characterised by attacks within the spinal cord and optic nerve. The purpose of this review is to understand the evidence for the effectiveness of plasmapheresis as an add-on therapy for NMO spectrum disorders (NMOSD). The current diagnostic criteria for NMO include optic neuritis, acute myelitis, and at least two of the following three supportive criteria: contiguous spinal cord MRI lesions extending over ≥3 vertebral segments, brain MRI not meeting diagnostic criteria for multiple sclerosis, and NMO-seropositive status.⁵ Myelitis presents with paraparesis and sensory loss below the lesion, sphincter loss, dysaesthesia, and radicular pain.