Follow-up of retinal thickness and optic MRI after optic neuritis in anti-MOG antibody-associated disease and anti-AQP4 antibody-positive NMOSD

Background: Retinal atrophy in the chronic phase of optic neuritis (ON) in anti-aquaporin-4 antibody (AQP4-Ab)-positive neuromyelitis optica spectrum disorder (NMOSD) and anti-myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) remains unclear. Methods: Patients with these diseases were repeatedly evaluated using optical coherence tomography (OCT) for the circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell complex (mGCC) in the ON-involved eyes during relapse-free period after the first ON episode before relapse. Optic MRI with short tau inversion recovery (STIR) sequences was further evaluated retrospectively. Results: Twelve patients with MOGAD (20 eyes with ON-involvement) and 14 with AQP4-Ab-positive NMOSD (16 eyes with ON-involvement) were enrolled. The progression of retinal atrophy ≥12 months after onset was observed in AQP4-Ab-positive NMOSD, but was not apparent in MOGAD. A decrease in retinal thickness by the same amount results in more severe visual impairment in AQP4-Ab-positive NMOSD. On optic MRI, the residual STIR hyperintensity in the optic nerves remained in the chronic phase in almost all eyes with ON in both diseases. Optic nerve atrophy occurred in all evaluated ON-involved eyes in AQP4-Ab-positive NMOSD, while it was observed in half of ON-involved eyes in MOGAD. Conclusions: Progression of retinal atrophy in the chronic phase has been observed in patients with AQP4-Ab-positive NMOSD, while it remains uncertain in patients with MOGAD. The visual impairments upon similar levels of retinal atrophy would be worse in AQP4-Ab-positive NMOSD, possibly attributable in part to a higher incidence of optic nerve atrophy in this disease.