Background/aim: The causes of atypical optic neuritis are different from typical demyelinating optic neuritis. It may exist as an isolated entity or may be part of a systemic process. Our aim was to determine the clinical characteristics, and therapeutic outcomes of isolated atypical optic neuritis in China. Methods: Inclusion criteria for isolated atypical optic neuritis required fulfillment of at least one of (1)-(3) and both (4), and (5): (1) Visual loss progressing for > 2 weeks since onset, (2) No visual recovery over 3 weeks after onset, (3) Worsening of vision over one line of acuity after withdrawal of corticosteroids, (4) No diagnosis of a defined collagen vascular disease or neurological autoimmune disease at onset, and (5) Neuro-ophthalmic follow-up for at least 12 months. Results: 20 cases fulfilled isolated atypical optic neuritis inclusion criteria. 10 cases (50%) were anti-aquaporin-4 antibody positive. 11 of 20 cases (55%) with flare of optic neuritis at the withdrawal of corticosteroids responded poorly to reinitiation of corticosteroid therapy. At the end of follow-up (median 41 month), vision in 60% of involved eyes (18/30 eyes) was still 20/200 or worse. Conclusions: In China, isolated atypical optic neuritis has a high incidence of anti-aquaporin-4 antibody and is resistant to corticosteroid therapy. (C) 2011 Elsevier B.V. All rights reserved.