Abstract: Objective To summarize the subtypes, clinical features, and treatment outcomes of optic neuritis (ON) patients presenting with altitudinal visual field defects. Design Retrospective case series. Participants Twenty-two ON patients with altitudinal visual field defects admitted to the Neurology Department of Beijing Tongren Hospital from January 2022 to June 2024. Method Clinical data, laboratory findings, imaging results, treatment and outcomes were collected and analyzed. Main Outcome Measures The degree of optic disc edema and presence of hemorrhage, Humphrey visual field index (VFI), optic nerve enhancement on MRI, best-corrected visual acuity (BCVA), serum demyelinating antibodies and rheumatological markers, cerebrospinal fluid oligoclonal bands (OCBs), presence of ocular or periocular pain, and treatment strategies. Results The study included 22 ON patients with a male-to-female ratio of 1:1 and a mean onset age of (45.6±12.6) years. Among them, 10 cases (45.5%) were diagnosed with single isolated optic neuritis (SION), 3 cases (13.6%) with MOG-IgG associated ON, 2 cases (9.1%) with AQP4-IgG associated ON, and 7 cases (31.8%) with autoimmune-related ON. Thirteen patients (59.1%) experienced ocular pain, and optic disc edema was observed in 19 eyes (86.4%), with 54.5% classified as mild. Seventeen patients (77.3%) demonstrated abnormal optic nerve signals on MRI, with involvement of the intraorbital segment in 16 cases (72.7%), canalicular segment in 6 cases (27.3%), and intracranial segment in 3 cases (13.6%). All patients received corticosteroid therapy during the acute phase, and 10 patients underwent immunosuppressive therapy during the remission phase. After three months, there was a significant improvement in VFI, with an average increase from (53.0±8.0)% at the onset of the disease to (79.8±13.5)% (P＜0.001), 7 eyes (31.8%) achieved complete visual recovery, 3 eyes (13.6%) experienced significant improvement in vision, and 6 eyes (27.3%) showed partial improvement，and 6 eyes(27.3%) showed no significant betterment or betterment that had not yet reached the level of  improvement. Conclusion Altitudinal visual field defects are associated with multiple ON subtypes, primarily involving the optic disc and anterior optic nerve. Treatment with corticosteroids and immunosuppressants contributes to a better recovery of visual function. (Ophthalmol CHN, 2024, 33: 429-434)

Key words:  optic neuritis, altitudinal visual field defects, magnetic resonance imaging