Vision disorders are the most prevalent class of handicapping conditions in childhood. Comprehensive eye examinations are recommended for preschool children because early detection increases the likelihood of effective treatment and allows for actions to decrease the negative impact of the disorders. However, less than 15 percent of all children receive an eye examination. Less than 20 percent of preschool children have some type of vision screening. The methods for vision screening vary tremendously and the effectiveness of the methods in appropriately identifying children has not been documented. Vision is Preschoolers (VIP) is a multi-center, prospective clinical study to evaluate candidate, screening tests for children aged 3 or 4 years. The screening tests are specifically targeted to identify children in need of further vision care for amblyopia, strabismus, or significant refractive error. The role of the Coordinating Center is to contribute to the success of VIP in fully evaluating the battery of screening tests through leadership, organization, communication, and facilitation of the execution of the study protocol. The Coordinating Center provides expertise on study design, statistical analysis, and data processing and management. The specific aims of the Coordinating Center to fulfill this role are: Work with the other members of the study group to further refine the study design; Create and maintain the study database through design of forms, data collection and processing, and data editing; Provide regular reports to all VIP centers and committees concerning study progress and performance; Provide interim and final statistical analysis of the accumulated data; Design and implement a full quality assurance program in conjunction with the Chairman's Office; Participate in the preparation of scientific presentations and reports.