Acute Optic Neuropathy in Older Adults Differentiating between MOGAD Optic Neuritis and Nonarteritic Anterior Ischemic Optic Neuropathy

Background and Objectives Myelin oligodendrocyte glycoprotein antibody-associated disease optic neuritis (MOGADON) and nonarteritic anterior ischemic optic neuropathy (NAION) can cause acute optic neuropathy in older adults but have different managements. We aimed to determine differentiating factors between MOGAD-ON and NAION and the frequency of serum MOG-IgG false positivity among patients with NAION. Methods In this international, multicenter, case-control study at tertiary neuro-ophthalmology centers, patients with MOGAD presenting with unilateral optic neuritis as their first attack at age 45 years or older and age-matched and sex-matched patients with NAION were included. Comorbidities, clinical presentations, acute optic disc findings, optical coherence tomography (OCT) findings, and outcomes were compared between MOGAD-ON and NAION. Multivariate analysis was performed to find statistically significant predictors of MOGAD-ON. A separate review of consecutive NAION patients seen at Mayo Clinic, Rochester, from 2018 to 2022, was conducted to estimate the frequency of false-positive MOG-IgG in this population. Results Sixty-four patients with unilateral MOGAD-ON were compared with 64 patients with NAION. Among patients with MOGAD-ON, the median age at onset was 56 (interquartile range [IQR] 50-61) years, 70% were female, and 78% wereWhite.Multivariate analysis showed that eye pain was strongly associated withMOGAD-ON(OR 32.905; 95% CI 2.299-473.181), while crowded optic disc (OR 0.033; 95% CI 0.002-0.492) and altitudinal visual field defect (OR 0.028; 95% CI 0.002-0.521) were strongly associated with NAION. On OCT, peripapillary retinal nerve fiber layer (pRNFL) thickness in unilateral MOGAD-ON was lower than in NAION (median 114 vs 201 μm, p < 0.001;median pRNFL thickening 25 vs 102 μm, p < 0.001).MOGAD-ONhadmore severe vision loss at nadir (median logMAR 1.0 vs 0.3, p < 0.001), but better recovery (median logMAR 0.1 vs 0.3, p = 0.002). In the cohort of consecutive NAION patients, 66/212 (31%) patients with NAION were tested for MOG-IgG and 8% (95% CI 1%-14%) of those had falsepositive serum MOG-IgG at low titers.