Methods to Assess Ocular Motor Dysfunction in Multiple Sclerosis

&NA; From the Section Editor: The JNO “Disease of the Year: Multiple Sclerosis” series concludes with a focus on cutting edge techniques used to qualitatively and quantitatively evaluate ocular motility abnormalities. In their article, “Methods to Assess Ocular Motor Dysfunction in Multiple Sclerosis,” Sheehy and colleagues expand on the earlier works published by Lee et al, and Nerrant et al, which provide an elegant overview of extra-ocular movement findings associated with brainstem disorders, and multiple sclerosis, respectively. The tools highlighted by Sheehy and colleagues add to our understanding of structure-function relationships in multiple sclerosis, and further expand the role of visual system models in multiple sclerosis research and clinical trials. In the series finale, “The International Multiple Sclerosis Visual System Consortium: Advancing Visual System Research in Multiple Sclerosis,” Balcer and colleagues chronicle the inception, development, and achievements of IMSVISUAL, a consortium created by clinicians and researchers committed to advancing the role of visual outcomes in the care of multiple sclerosis patients. The ingenuity and accomplishments of IMSVISUAL will serve to inspire other international collaborations, and further advance scientific discovery in the field of neuro-ophthalmology. Background: Multiple sclerosis (MS) is an inflammatory disease of the central nervous system causing the immune-mediated demyelination of the brain, optic nerve, and spinal cord and resulting in ultimate axonal loss and permanent neurological disability. Ocular motor dysfunction is commonly observed in MS but can be frequently overlooked or underappreciated by nonspecialists. Therefore, detailed and quantitative assessment of eye movement function has significant potential for optimization of patient care, especially for clinicians interested in treating visual symptoms or tracking disease progression. Methods: A brief history of eye tracking technology followed by a contextualized review of the methods that can be used to assess ocular motor dysfunction in MS—including a discussion of each method's strengths and limitations. We discuss the rationale for interest in this area and describe new tools capable of tracking eye movements as a possible means of monitoring disease. Results/Conclusions: This overview should inform clinicians working with patients with MS of how ocular motor deficits can best be assessed and monitored in this population. It also provides a rationale for interest in this field with insights regarding which techniques should be used for studying which classes of eye movements and related dysfunction in the disease.