Neuromyelitis Optica Spectrum Disorder–Related Optic Neuritis Mimicking Idiopathic Orbital Inflammation

The authors report a case of neuromyelitis optica spectrum disorder–related optic neuritis. The patient showed rapid vision loss in both eyes, and brain magnetic resonance imaging indicated perineuritis due to idiopathic orbital inflammation. Although minor improvement was noted following corticosteroid pulse therapy, the patient’s vision worsened after 7 days. Further evaluation revealed anti-aquaporin-4 antibody positivity, therefore the authors diagnosed the case as neuromyelitis optica spectrum disorder. This case suggests that patients with severe bilateral visual loss and poor corticosteroid response should be tested for anti-aquaporin-4 antibody and may require further aggressive management.