Foveal changes in AQP4-Ab seropositive NMOSD are independent of optic neuritis and not overtly progressive.

BACKGROUND Foveal changes were reported in Aquaporin-4 antibody(AQP4-Ab) seropositive neuromyelitis optica spectrum disorder(NMOSD) patients; however, it is unclear whether they are independent of ON, stem from subclinical ON or crossover from ON in fellow eyes. AIM We used fovea morphometry and a statistical classification approach to investigate if foveal changes in NMOSD are independent of ON and progressive. METHODS Retrospective longitudinal study of 27 AQP4-IgG+ NMOSD patients (49 eyes; 15 ON-eyes and 34 eyes without a history of ON(NON-eyes)), follow-up median (1st and 3rd quartile): 2.32 (1.33-3.28) and 38 healthy controls(HC)(76 eyes), follow-up median (1st and 3rd quartile) 1.95 (1.83-2.54). Peripapillary retinal nerve fibre layer thickness(pRNFL) and volumes of combined ganglion cell and inner plexiform layer (GCIP) as measures of neuroaxonal damage from ON were determined by optical coherence tomography(OCT). Nineteen foveal morphometry parameters were extracted from macular OCT volume scans. Data was analysed using orthogonal partial least squares discriminant analysis(OPLS-DA) and linear mixed-effects models. RESULTS At baseline, foveal shape was significantly altered in ON eyes and NON-eyes compared to HC. Discriminatory analysis showed 81% accuracy distinguishing ON Vs HC and 68% accuracy in NON Vs HC. NON-eyes were distinguished from HC by foveal shape parameters indicating widening. OPLS-DA discriminated ON Vs NON with 76% accuracy. In a 2.4(20.85) years follow-up, we found no significant time-dependent foveal changes. CONCLUSION The parafoveal area is altered in AQP4-Ab seropositive NMOSD patients suggesting independent neuroaxonal damage from subclinical ON. Longer follow-ups are needed to confirm the stability of the parafoveal structure over time.