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

AIM: To compare retinal ganglion cell function between optic neuritis (ON) cases positive for anti-aquaporin-4 antibody (AQP4+) and myelin oligodendrocyte glycoprotein (MOG+).

METHODS

Patients tested positive for AQP4 or MOG and history of ON at least six months prior to enrollment were included. An ophthalmological examination, visual acuity test (BCVA), visual field test (mean deviation, MD) and spectral-domain optical coherence tomography (OCT) were performed. Full-field electroretinography (ERG) was recorded following the ISCEV standard, extended by a red flash (640 nm, 2 cd.s/m2) with a blue background (460 nm, 10 cd/m2) to elicit a photopic negative response (PhNR).

RESULTS

A total of 23 AQP4+ and 15 MOG+ patients were included. BCVA (logMAR) was significantly worse in AQP4+ ON eyes (1.11 ± 0.25) compared to MOG+ ON eyes (0.22 ± 0.07; p = 0.0071). RNFL thickness did not differ significantly between groups (AQP4+: 58.37 ± 3.82 µm; MOG+: 63.29 ± 4.14 µm; p = 0.6622), but mGCL was significantly thinner in AQP4+ ON eyes (27.23 ± 1.92 µm vs. 35.99 ± 1.86 µm; p = 0.0059). PhNR amplitude was lower in AQP4+ ON eyes (-20.69 ± 2.27 µV) than in both controls (-37.88 ± 2.27 µV; p < 0.0001) and MOG+ ON eyes (-31.54 ± 2.57 µV; p = 0.0024). In AQP4+ ON, PhNR amplitude showed significant correlations with visual field MD (r = 0.656, p = 0.0031) and GCL (r = -0.684, p = 0.0071).

CONCLUSION

Visual and functional impairment in AQP4+ ON eyes was more severe and correlated with structural loss. In contrast, MOG+ ON eyes showed dissociation between structure and function, suggesting post-retinal or central compensatory mechanisms.