['Determine the utility of optical coherence tomography (OCT) to detect clinical and subclinical remote optic neuritis (ON), its relationship to clinical characteristics of ON and visual function, and whether the retinal nerve fiber layer (RNFL) thickness functions as a surrogate marker of global disease severity.', 'Cross-sectional study of 65 subjects with at least 1 clinical ON episode at least 6 months prior. Measures included clinical characteristics, visual acuity (VA), contrast sensitivity (CS), OCT, and visual evoked potentials (VEP).', 'Ninety-six clinically affected optic nerves were studied. The sensitivity of OCT RNFL after ON was 60%, decreasing further with mild onset and good recovery. VEP sensitivity was superior at 81% (p = 0.002). Subclinical ON in the unaffected eye was present in 32%. VEP identified 75% of all subclinically affected eyes, and OCT identified <20%. RNFL thickness demonstrated linear correlations with VA (r = 0.65) and CS (r = 0.72) but was unable to distinguish visual categories <20/50. RNFL was thinner with severe onset and disease recurrence but was unaffected by IV glucocorticoids. OCT measurements were not related to overall disability, ethnicity, sex, or age at onset. The greatest predictor for RNFL in the unaffected eye was the RNFL in the fellow affected eye.'] Is optical coherence tomography less sensitive than visual evoked potentials in optic neuritis?