Retinal Nerve Fiber Layer and Optic Nerve Head Measurements in Eyes without Optic Neuritis: A Spectral-Domain OCT Comparison Across MOGAD, MS, and Controls

To evaluate and compare peripapillary retinal nerve fiber layer (pRNFL) thickness and optic nerve head (ONH) structural parameters using spectral-domain optical coherence tomography (SD-OCT) in non-optic neuritis (NON) eyes of patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), multiple sclerosis (MS), and healthy controls (HC). This retrospective observational study included three groups: patients with MOGAD, patients with MS, and age- and sex-matched healthy controls. Only NON eyes – those without clinical or radiological evidence of optic neuritis and with negative visual evoked potentials – were included for MOGAD and MS patients. OCT imaging (Cirrus HD-OCT, Carl Zeiss Meditec) was performed to measure average and quadrant-specific pRNFL thickness, along with ONH parameters. A total of 63 participants (45 females, 71.4%) were included: 21 in each group (MOGAD, MS, and HC). The mean age was 37.5 ± 9.8 years. Average pRNFL thickness differed significantly among the groups (p = 0.001), being lower in MS compared to MOGAD and HC. Optic disc area was significantly larger in MOGAD (p = 0.03). No significant differences were noted in rim area or cup-to-disc ratios, but cup volume was significantly greater in HC (p = 0.002). MOGAD patients without optic neuritis exhibited preserved pRNFL thickness comparable to healthy controls, suggesting an absence of subclinical axonal loss. MS patients showed reduced pRNFL thickness despite no clinical ON, indicating subclinical neurodegeneration. The larger optic disc area in MOGAD may represent a disease-specific anatomical trait warranting further study.