Subclinical optic neuritis in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease

Background and objectives The clinical spectrum of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is heterogenous and has evolved over time since the commercial availability of the anti-MOG antibody assay. Subclinical disease activity has been previously reported in the visual pathway, but prevalence data remains limited. We investigated subclinical optic neuritis (ON) based on changes on retinal nerve fiber layer (RNFL) thickness on optic coherence tomography (OCT) in pediatric patients who test positive for the anti-MOG antibody. Methods In this retrospective, single-center cohort study, we examined children with MOGAD with at least one complete assessment of the anterior visual pathway. Subclinical ON was defined by structural visual system disease in the absence of a subjective complaint of vision loss, pain (particularly with eye movement), or color desaturation. Results Records were reviewed from 85 children with MOGAD, 67 of whom (78.8%) had complete records for review. Eleven children (16.4%) had subclinical ON on OCT. Ten had significant reductions in RNFL, of which one had two distinct episodes of decreased RNFL, and one had significant elevations in RNFL. Of the eleven children with subclinical ON, six (54.5%) had a relapsing disease course. We also highlight the clinical course of three children with subclinical ON detected on longitudinal OCT, including two who had subclinical ON outside of clinical relapses. Conclusion Children with MOGAD can have subclinical ON events that can manifest as significant reductions or elevations in RNFL on OCT. OCT should be used routinely in the management and monitoring of MOGAD patients.