MOGAD Is the Most Common Cause of Isolated Optic Neuritis in Children.

OBJECTIVES

The study aimed to characterize the clinical features, etiologies, and outcomes of isolated, first-time pediatric ON in the post-MOG-IgG era.

METHODS

This was a single-center retrospective cohort study at Texas Children's Hospital of patients diagnosed with first-time ON between 2018-2024, with follow-up data collected through 2025. Inclusion criteria required monocular or binocular subacute vision loss with supportive paraclinical signs. Subjects were excluded if they had a prior history of demyelinating disease or extra-orbital demyelinating lesions on initial brain/spine MRI. Primary outcomes were the proportion of MOG-IgG seropositivity, retinal nerve fiber layer thickness, and visual acuity at onset and most recent follow-up.

RESULTS

Of 73 children with ON, 38 met criteria for isolated first-time ON. Etiologies included MOGAD (n = 27, 71.1%) and idiopathic/monophasic (n = 9, 23.7%), while none of the 38 subjects were later diagnosed with multiple sclerosis. MOGAD-ON was associated with less severe vision loss at presentation (p < 0.01) compared to idiopathic cases. At most recent follow-up, both groups achieved excellent functional recovery, yet both demonstrated significant retinal nerve fiber layer thinning from ON presentation. Linear regression revealed worse presenting LogMAR significantly correlated to thinner follow-up RNFL (F(1,18) = 8.467, R2 = 0.32, p < 0.01). One (3.7%) MOGAD-ON patient relapsed during follow-up.

INTERPRETATION: In isolated pediatric ON, no patients were diagnosed with MS, and MOGAD is the predominant etiology. The linear correlation between initial LogMAR and subsequent RNFL atrophy suggests a permanent reduction in neurological reserve dependent on the degree of functional severity at ON onset.