Structural and functional biomarkers of visual dysfunction in MOG antibody-positive optic neuritis: a scoping review.

INTRODUCTION

Myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) commonly manifests as optic neuritis (ON) in association with serum MOG immunoglobulin G (MOG-IgG). This review will evaluate the literature on visual dysfunction in MOG-IgG ON, with a focus on ophthalmic structural biomarkers and ancillary outcome measures.

METHODS

PubMed was systematically searched using the terms "optic neuritis", "visual outcomes" and "myelin-oligodendrocyte glycoprotein" between 2007 to January 2025. High-contrast visual acuity (HCVA), low-contrast visual acuity (LCVA), contrast sensitivity, visual fields (VF), electrophysiology, optical coherence tomography (OCT)/angiography, magnetic resonance imaging (MRI) and quality of life (QoL) were evaluated.

RESULTS

35 studies and 2335 patients were included. 89 % of studies reported HCVA. OCT and MRI were reported in 63 % and 43 % of studies, respectively. MOG-IgG ON had moderate-severe HCVA loss at nadir but good HCVA recovery. MRI features characteristic to MOG-IgG ON include longitudinally extensive lesions +/- perineural enhancement. OCT in acute MOG-IgG ON revealed moderate-severe peripapillary retinal nerve fibre layer (p-RNFL) swelling. However severe axonal loss was noted in chronic outcomes, despite preservation of HCVA, highlighting a recognised structure-function discordance. Only 31 % reported on VFs, 17 % on LCVA, and 14 % on VEPs, all of which demonstrated abnormalities even in patients with normal HCVA. Only one study reported on contrast sensitivity or QoL.

CONCLUSION

Current clinical assessments may underestimate visual dysfunction in MOG-IgG ON. Prospective, longitudinal multimodal evaluation should be a key focus for future research, to identify the most sensitive biomarkers to be incorporated into routine clinical practice. This will better identify patients at risk of adverse visual outcomes in MOG-IgG ON, guide clinical management and improve QoL.