Regarding the natural severity of NMOSD-ON, the disease resulted in poor long-term visual outcomes, with a final VA of worse than 20/200 [19,20,21,22], since the histopathology of NMOSD entails autoantibodies attacking the site of AQP4-expression (such as the optic nerve, spinal cord lesions), resulting in astrocytic damage at the optic nerve in patients with optic neuritis. This evidence concerns the gene AQP4 and optic neuritis.