This proposal is for the Pennsylvania College of Optometry (PCO) to service as one of five clinical centers designed to develop an effective and efficient battery of screening tests to identify those 3- and 40 year-old Head Start children in need of further vision care for amblyopia, strabismus, and/or significant refractive error, that are the prevalent significant vision disorders of early childhood. To accomplish these goals, a battery of vision screening tests will be administered to 1278 three- and four year-old children enrolled in Head Start throughout Philadelphia. The battery consists of tests chosen for their design characteristics, validity, and applicability to the preschool population, and includes the Lea visual acuity test at distance, the Random Dot E and Retinomax Autorefractor. This battery of tests will be administered at Head Start sites by lay people (Head Start parents), which ensures availability of screeners, utilizes persons with a vested interest in benefitting children within their community, empowers communities toward self improvement and maximizes the applicability of this model to other communities. Each child who fails the screening or is untestable, and a randomly selected subset of children who pass the screening, will undergo a comprehensive eye examination at the Pennsylvania College of Optometry (PCO). The examination will serve as the definitive method, or gold standard for detection of the target disorders will be determined for each of the screening battery tests alone, and in combination. This application documents: a) access of the PCO Clinical Center to 1750 children enrolled in Head Start and b) that facilities and personnel are available for conducting vision screenings at the Head Start sites and for conducting gold standard eye examinations. Complete details of the VIP Study rationale, design and methods are contained in the MP, which is submitted with the Study Chair application.