Elias Sotirchos, MD, Johns Hopkins University School of Medicine, Baltimore, MD, shares the findings of a study of retinal later atrophy in multiple sclerosis (MS) using serial optical coherence tomography (OCT). OCT-derived retinal measures have been suggested as a potential biomarker of neurodegeneration in progressive MS. Thus, patients with progressive MS, relapsing-remitting MS (RRMS) and control participants were assessed using OCT for a median of 3.7 years. Results showed that progressive MS was associated with faster retinal atrophy compared to RRMS, independent of age. Inner nuclear layer (INL) and outer nuclear layer (ONL) thinned faster in PMS than in RRMS and controls, and thinning rate was not impacted by disease modifying therapies, highlighting these measures as potential novel biomarkers of neurodegeneration in MS. This interview took place during the ACTRIMS Forum 2021.