Unique characteristics of optical coherence tomography (OCT) results and visual acuity testing in myelin oligodendrocyte glycoprotein (MOG) antibody positive pediatric patients

Background: Optic nerve involvement in anti-myelin oligodendrocyte glycoprotein antibody associated syndrome (MOG ab syndrome) tends to have unique features. Few studies have reported optical coherence tomography (OCT) measures like retinal nerve fiber layer thickness findings in the setting of pediatric MOG ab syndrome. Objectives: The aim of this study is to compare visual acuity between MOG ab positive and MOG ab negative pediatric cohorts and examine correlations with OCT findings. Methods: We included outpatients less than 18 years of age who had optic neuritis (ON) of at least one eye and who completed visual testing and OCT in the study. ON was defined based on clinical or OCT findings. Antibody testing was obtained using cell-based assay. The primary analyses of interest investigated differences in low-contrast visual acuity stratified by the defined RNFL ranges and by antibody positivity. Results: We analyzed 28 eyes from 14 anti-MOG ab patients (MOG-ON cohort), 18 eyes from 9 anti-AQP4 ab (AQP4-ON cohort) patients and 26 eyes from 13 patients who tested negative for both the antibodies (seronegative ON cohort). MOG-ON eyes with zero reported clinical events had lower RNFL thickness, than the minimum RNFL thickness of either the seronegative-ON or AQP4-ON eyes with zero clinical attacks in most retinal segments. Within the lowest range of the RNFL (RNFL <50 um) in most retinal segments, the MOG-ON cohort had a statistically significant greater visual acuity relative to the AQP4 cohort. Conclusions: Patients with anti-MOG antibody mediated CNS disorders can suffer from subclinical ON events with significant reductions in RNFL. Despite equally significant damage to the optic nerve, MOG-Ab positive patients have relatively preserved visual acuity.