OCT Measurement May Help Differentiate MOGAD-Related Optic Neuritis From NMOSD at Onset

A recently published study reported that peripapillary retinal nerve fiber layer (pRNFL) thickness, measured through optical coherence tomography (OCT), differed significantly between patients with myelin oligodendrocyte glycoprotein antibody-associated disease–related optic neuritis (MOGAD-ON) and aquaporin-4 antibody–positive neuromyelitis optica spectrum disorder–related optic neuritis (NMOSD-ON). These findings suggest that OCT may aid in early differentiation between these rare autoimmune conditions prior to antibody confirmation.¹

In the analysis, investigators included 83 patients with MOGAD (women, n = 51; ON eyes, n = 124; bilateral ON, 48.2%) and 28 with NMOSD (women, n = 24; ON eyes, n = 36; bilateral ON, 21.4%) who experienced a first episode of unilateral or bilateral ON. Overall, findings showed that the mean pRNFL thickness was higher in the MOGAD group compared with the NMOSD group (157.4 [±63.7] µm vs 101.5 [±26.8] µm; P <.001).

Researchers also reported that an increase in pRNFL thickness greater than 115 µm (>2 SDs), consistent with disc edema, was observed in 73.4% of MOGAD-ON eyes and 11.1% of NMOSD-ON eyes (P <.001). Notably, an ROC analysis comparing pRNFL thickness in acute MOGAD-ON compared with NMOSD-ON provided a cutoff of 117.5 µm, where thicker pRNFL significantly favored MOGAD-ON over NMOSD-ON (AUC = 0.838, 92.9% specificity, 71.1% sensitivity).

“Clinical differentiation between MOGAD and NMOSD during the first ON episode is often challenging and treatment relevant. Optic disc edema is primarily characteristic of MOGAD-ON; however, its prevalence, severity, and clinical applicability, as measured by OCT, in the differentiation from NMOSD-ON have not been systematically investigated previously,” senior author Ilya Ayzenberg, MD, Deputy Director of the Clinic for Neurology at The Ruhr University Bochum in Germany, and colleagues wrote.¹

In this multicenter, retrospective, cross-sectional study, investigators evaluated the utility of OCT for differentiating first-episode acute optic NMOSD-ON and MOGAD-ON, as well as factors associated with disc edema. The analysis included 111 adult patients diagnosed with MOGAD according to the 2023 Banwell criteria or aquaporin-4 antibody–positive NMOSD based on the 2015 International Panel for NMO Diagnosis criteria from 14 centers across 8 countries who underwent OCT in 14 days of ON onset.^2,3 For this study, researchers specifically assessed pRNFL thickness, with mean values calculated across affected eyes, including bilateral cases.

READ MORE: Real-World Study Demonstrates FDA-Approved NMOSD Therapies Outperform Rituximab on Relapse Outcomes

In a supplementary analysis, pRNFL thickness was not associated with age or sex in either group. In patients with MOGAD, there was no significant association between pRNFL thickness and sex (P = .288) or age (P = .200). Similarly, no associations were observed in patients with NMOSD for sex (P = .776) or age (P = .876).

When stratified by body mass index (BMI), defined as normal (<25 kg/m²) versus elevated (≥25 kg/m²), no significant differences in pRNFL thickness were observed in either group. In MOGAD, mean pRNFL thickness was 160.1 [±75.4] µm in patients with BMI <25 and 159.1 [±55.9] µm in those with BMI of at least 25 (P = .440). In NMOSD, corresponding values were 99.3 [±11.9] µm and 112.0 [±41.6] µm, respectively (P = .910).

In the MOGAD group, simultaneous bilateral optic neuritis was associated with significantly greater pRNFL thickening compared with unilateral involvement (194.4 [±81.8] µm vs 155.4 [±76.6] µm; P = .006). In contrast, among patients with NMOSD-associated optic neuritis, pRNFL thickness was higher in eyes with unilateral involvement than in those with bilateral disease (109.5 [±32.3] µm vs 86.3 [±16.7] µm; P = .005).

“OCT should be considered as a relevant acute-stage diagnostic tool in patients with first ON, helpful in the rapid differentiation between MOGAD-ON and NMOSD-ON, particularly in patients with pRNFL thickening,” Ayzenberg et al noted.¹ “This diagnostic approach is especially relevant in severe and/or bilateral ON, characteristic of NMOSD and MOGAD, because immediate escalation to plasmapheresis is critical in NMOSD-ON and may be warranted before antibody results are available.”

REFERENCES
1. Pakeerathan T, Davis J, Henderson AD, et al. OCT-Based Differentiation of First Acute Optic Neuritis: An International Study of 111 Patients With NMOSD and MOGAD. Neurol Neuroimmunol Neuroinflamm. 2026;13(2):e200531. doi:10.1212/NXI.0000000000200531
2. Banwell B, Bennett JL, Marignier R, et al. Diagnosis of myelin oligodendrocyte glycoprotein antibody-associated disease: International MOGAD Panel proposed criteria. Lancet Neurol. 2023;22(3):268-282. doi:10.1016/S1474-4422(22)00431-8
3. Wingerchuk DM, Banwell B, Bennett JL, et al. International consensus diagnostic criteria for neuromyelitis optica spectrum disorders. Neurology. 2015;85(2):177-189. doi:10.1212/WNL.0000000000001729