Celia Oreja-Guevara, MD, PhD, University Hospital San Carlos, Madrid, Spain, talks about visual alterations in patients with multiple sclerosis (MS). This is an important symptom when patients are in early phases of MS because it indicates that a patient has optic neuritis (i.e., inflammation of the optic nerve). When using normalized tests (e.g., Ishihara color test), patients usually score highly, suggesting they do not have problems with perceiving colors. However, a recent study using ophthalmologist tests on 50 eyes, such as the Farnsworth Munsell D28 test, showed that patients with optic neuritis had chromatic alterations. Additionally, patients with optic neuritis had worse low contrast visual acuity and worse contrast sensitivity than those without optic neuritis. Potentially, visual changes on the Munsell test could be used as progression markers to follow patients and identify which patients should be treated with visual training. This interview took place at the European Academy of Neurology (EAN) 2022 Congress in Vienna, Austria.