Discriminative Abilities of Macular and Retinal Nerve Fiber Layer Thickness in Multiple Sclerosis and Optic Neuritis

To determine the discriminative abilities of macular and retinal nerve fiber layer (RNFL) thicknesses in multiple sclerosis (MS) from normal and to identify optic neuritis (ON) in MS patients.

This cross-sectional case-control study included 133 participants aged 30-45 years: 66 definite MS patients (18 with ON) and 67 age- and sex-matched healthy controls. MS diagnosis was established ≥5 years before enrollment. Exclusion criteria were other neurological/retinal diseases, high refractive error (> ±6.00 diopter), media opacities, glaucoma, or intraocular surgery. All underwent spectral-domain optical coherence tomography (Cirrus High-Definition Optical Coherence Tomography) under pharmacologic mydriasis to measure RNFL and macular thicknesses.

MS patients without ON showed significantly reduced macular thickness in inner superior, outer inferior, outer superior, outer nasal, and outer temporal sectors versus controls. MS patients with ON had significantly thinner inner superior and outer superior macular sectors than those without ON. For distinguishing MS from controls, an average RNFL ≤94 μm yielded a sensitivity of 87.9%, a specificity of 70.2%, and the area under the receiver operating characteristic curve (AUC) of 0.836 (P < 0.001). For differentiating MS with versus without ON, the average RNFL ≤83 μm achieved the highest RNFL performance: AUC of 0.836, sensitivity of 72.2%, and specificity of 81.3%. Among macular subregions, outer nasal (AUC = 0.680) and outer superior (AUC = 0.670) sectors best distinguished MS from controls. For ON detection, the outer superior sector performed best (AUC = 0.736, sensitivity: 61.1%, and specificity: 79.2%).

RNFL thinning is a robust structural biomarker for MS and prior ON, whereas average macular thickness has limited standalone diagnostic utility for ON, though specific outer macular sectors show moderate discriminative value.