It is essential to assess the severity of multiple sclerosis (MS) in order to choose appropriate therapeutic measures, but this cannot be reliably done using existing methods. A MedUni Vienna study now shows for the first time that the retina can be used as a prognostic marker. Analyses revealed that retinal layer thinning as a result of an MS relapse predicts the severity of future relapses and, hence, the likelihood of disability. The results of the study have now been published in Neurology.