Retinal ganglion cell function in AQP4+ and MOG+ optic neuritis

Area of Science:

• Neuro-ophthalmology
• Immunology of the nervous system
• Retinal imaging and electrophysiology

Background:

• Optic neuritis (ON) can be associated with antibodies against aquaporin-4 (AQP4+) or myelin oligodendrocyte glycoprotein (MOG+).
• Differentiating AQP4+ ON and MOG+ ON is crucial for prognosis and treatment.
• Retinal ganglion cell function and structure are key indicators of visual pathway integrity.

Purpose of the Study:

• To compare retinal ganglion cell function and structure in patients with AQP4+ ON versus MOG+ ON.
• To investigate the relationship between visual function, retinal structure, and antibody status in ON.

Main Methods:

• Included patients with a history of ON and positive serological tests for AQP4 or MOG.
• Performed ophthalmological examinations, best corrected visual acuity (BCVA), visual field tests (mean deviation, MD), and spectral-domain optical coherence tomography (OCT).
• Recorded full-field electroretinography (ERG) including photopic negative response (PhNR) to assess retinal ganglion cell function.

Main Results:

• AQP4+ ON eyes had significantly worse BCVA and thinner inner retinal layers (mGCL) compared to MOG+ ON eyes.
• PhNR amplitude was significantly reduced in AQP4+ ON eyes compared to both controls and MOG+ ON eyes.
• In AQP4+ ON, PhNR amplitude correlated with visual field MD and GCL thickness, indicating functional-structural relationships.

Conclusions:

• Visual and functional impairment is more severe in AQP4+ ON and correlates with structural damage.
• MOG+ ON eyes exhibit a dissociation between structure and function, possibly due to post-retinal or central compensatory mechanisms.
• These findings highlight distinct pathophysiological pathways and clinical outcomes in AQP4+ and MOG+ ON.