Visual impairment is a leading cause of symptoms in patients with multiple sclerosis (MS). Despite the importance of vision to disability and health-related quality of life (HRQOL) in MS, the measurement of visual function in MS trials has been limited to measures of Snellen visual acuity. The extent to which vision has been affected by new therapies for MS is not known, and has been difficult to assess using traditional measures of neurologic impairment. The visual profile of MS has not been examined, and the relation of visual function to overall neurologic impairment and to vision- and disease-specific HRQOL in patients with MS has not been determined in a large, heterogeneous cohort. This proposal will accomplish the following specific aims: 1. Define the visual profile of MS in a large cohort (400 patients), and determine which measures best identify visual dysfunction in patients with MS. The vision tests which best distinguish MS patients from an age-matched control group will be identified from among five candidate measures using analysis of variance (ANOVA), receiver operating characteristic curve (ROC) area analysis, and discriminant function analysis. Visual function measures will include visual acuity, contrast letter acuity, contrast sensitivity, color vision, and visual field. The relation of vision scores to overall neurologic impairment (Expanded Disability Status Scale, MS Functional Composite scores) will also be examined using linear regression and correlation techniques. 2. Determine the relation of visual function to vision- and disease-specific HRQOL in patients with MS. Linear regression and correlation techniques will be used to determine the relation of vision scores to vision- and disease-specific HRQOL scores, using the Multiple Sclerosis Quality of Life Inventory (MSQLI) and the 25Item National Eye Institute Visual Function Questionnaire (VFQ-25). The proposed research will contribute significantly to our understanding of visual dysfunction in MS, its relation to neurologic function, and its impact on vision- and disease-specific HRQOL. Results from this project will also advance outcomes assessment for MS research and clinical trials, allowing for more efficient monitoring and development of MS therapies. This proposal will provide a crucial foundation for future studies of vision in MS that will involve longitudinal assessment.