Longitudinal optical coherence tomography study of optic atrophy in secondary progressive multiple sclerosis: Results from a clinical trial cohort

Limited prospective information exists regarding spectral-domain optical coherence tomography (SD-OCT) in secondary progressive multiple sclerosis (SPMS). Document cross-sectional and longitudinal retinal nerve fiber layer (RNFL) and macular ganglion cell plus inner plexiform layer (GCIPL) features of an SPMS clinical trial cohort. Prospective, observational study using a 2-year randomized placebo-controlled SPMS trial cohort with yearly SD-OCT testing. Post hoc analysis determined influences of optic neuritis (ON), disease duration, and baseline SD-OCT on annualized atrophy rates and on correlations between OCT and brain atrophy. Mean RNFL and GCIPL values of patients (n = 47, mean age = 59 years, mean disease duration = 30 years) were significantly lower among eyes with prior ON than those without (no history of ON (NON)). Annualized RNFL (？0.31 μm/year) and GCIPL (？0.29 μm/year) atrophy rates did not differ between ON and NON eyes. Baseline RNFL thickness >75 μm was associated with greater annualized RNFL atrophy (？0.85 μm/year). Neither RNFL nor GCIPL atrophy correlated with whole-brain atrophy. This study suggests that eyes with and without ON history may be pooled for atrophy analysis in SPMS clinical trials using SD-OCT. Low baseline RNFL, small retinal atrophy rates, and lack of correlation with whole-brain atrophy in this population are important trial design considerations