Low-Contrast Letter Acuity Loss Over Time in Multiple Sclerosis Correlates with Reductions in Retinal Nerve Fiber Layer Thickness and Macular Volume by OCT

Low-contrast letter acuity testing is being used with increasing frequency as an MS trial outcome. This measure demonstrated treatment effects in recent phase 3 trials of natalizumab, capturing sustained, clinically-significant visual loss. Optical coherence tomography (OCT) parameters of retinal nerve fiber layer (RNFL) thickness and macular volume are reduced in eyes of MS patients, and also demonstrate promise as MS trial endpoints. We sought to examine correlations between low-contrast letter acuity losses over time with changes in RNFL thickness and macular volume in an MS cohort.