Aquaporin-4 IgG seropositivity is associated with worse visual outcomes after optic neuritis than MOG-IgG seropositivity and multiple sclerosis, independent of macular ganglion cell layer thinning

Background: Comparative studies of characteristics of optic neuritis (ON) associated with myelin oligodendrocyte glycoprotein-IgG (MOG-ON) and aquaporin-4-IgG (AQP4-ON) seropositivity are limited. Objective: To compare visual and optical coherence tomography (OCT) measures following AQP4-ON, MOG-ON, and multiple sclerosis associated ON (MS-ON). Methods: In this cross-sectional study, 48 AQP4-ON, 16 MOG-ON, 40 MS-ON, and 31 healthy control participants underwent monocular letter-acuity assessment and spectral-domain OCT. Eyes with a history of ON >3 months prior to evaluation were analyzed. Results: AQP4-ON eyes exhibited worse high-contrast letter acuity (HCLA) compared to MOG-ON (-22.3 +/- 3.9 letters; p < 0.001) and MS-ON eyes (-21.7 +/- 4.0 letters; p < 0.001). Macular ganglion cell + inner plexiform layer (GCIPL) thickness was lower, as compared to MS-ON, in AQP4-ON (-9.1 +/- 2.0 mu m; p < 0.001) and MOG-ON (-7.6 +/- 2.2 mu m; p = 0.001) eyes. Lower GCIPL thickness was associated with worse HCLA in AQP4-ON (-16.5 +/- 1.5 letters per 10 mu m decrease; p < 0.001) and MS-ON eyes (-8.5 +/- 2.3 letters per 10 mu m decrease; p < 0.001), but not in MOG-ON eyes (-5.2 +/- 3.8 letters per 10 mu m decrease; p = 0.17), and these relationships differed between the AQP4-ON and other ON groups (p < 0.01 for interaction). Conclusion: AQP4-IgG seropositivity is associated with worse visual outcomes after ON compared with MOG-ON and MS-ON, even with similar severity of macular GCIPL thinning.