ABSTRACT
While the exact cause is unknown, the pathophysiology of multiple sclerosis (MS) is that of inflammatory demyelination in the central nervous system, including the optic nerves and structures in the afferent visual pathways1,2. Although MS was previously thought to be exclusively a disease of myelin with sparing of nerve axons, neuronal and axonal loss are now recognized as prominent components of disease that lead to permanent neurological and visual impairment1-8. Research designed to improve outcome measures in MS, including those related to visual loss, will have a significant impact upon our efforts to reduce the burden of MS disability. Since long-term disability in MS is likely to reflect both the number of exacerbations and the degrees of axonal and neuronal loss, clinical trials that examine neuroprotective as well as immunomodulatory agents will require measures that non-invasively assess the integrity of nerve cells and their axons.
