Optic neuritis in Asian type opticospinal multiple sclerosis (OSMS-ON) in a non-Asian population: A...

Area of Science:

• Neuroscience
• Ophthalmology
• Immunology

Background:

• Biomarkers aid in classifying autoimmune inflammatory disorders like optic neuritis (ON), multiple sclerosis, neuromyelitis spectrum disorders, MOG antibody-related disease (MOGAD), and opticospinal multiple sclerosis (OSMS).
• The clinical presentation of OSMS in non-Asian populations remains less understood.

Purpose of the Study:

• To investigate the clinical characteristics and prognosis of OSMS-ON in a Brazilian cohort.
• To evaluate visual acuity, visual field, and retinal structure in OSMS patients compared to healthy controls.

Main Methods:

• A single-center cohort study in Rio de Janeiro, Brazil, included MOG- and AQP4-seronegative patients diagnosed with OSMS-ON and transverse myelitis (TM).
• Assessed visual acuity (VA), mean deviation (MD) from automated perimetry, intraocular pressure, and optical coherence tomography (OCT) for peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell and inner plexiform layer (mGCIPL) thickness.
• Analyzed retinal asymmetry using receiver operator characteristic curves (AUC) to differentiate patients from healthy controls.

Main Results:

• The study included 30 OSMS patients (predominantly female, white, mean age 48 years); 83.3% presented with unilateral ON.
• Over an 18-year follow-up, 89 ON relapses occurred. Patients showed significant cumulative loss in VA and MD with recurrent episodes.
• Significant atrophy was observed in pRNFL and mGCIPL in OSMS patients compared to healthy controls (p<0.0001).
• Retinal asymmetry metrics accurately distinguished OSMS patients from controls (AUC=0.89 and 0.85).

Conclusions:

• A structural-functional paradox exists in OSMS, with substantial inner retinal damage but preserved visual function.
• Retinal asymmetry presents a novel, highly diagnostic metric for OSMS.
• Despite high relapse rates and structural damage, OSMS patients exhibit excellent long-term visual outcomes.