OBJECTIVES. Visual disorders among preschool-aged children are common, yet screening is infrequent. The purpose of this project was to implement the vision screening recommendations proposed by the Maternal and Child Health Bureau and National Eye Institute Vision Screening in the Preschool Child Task Force: monocular visual acuity and stereopsis testing.METHODS. Four sites fully participated in the implementation of the task force recommendations with 3-and 4-year-old children. Two of the sites worked with primary care practices (testing performed by staff); 2 worked with communitybased programs (testing performed by lay volunteers). Each site tracked number of children screened by age, as well as proportion testable, referred, and with documented follow-up evaluation.RESULTS. Variations in implementation of the recommendations were observed. Successful screening among 3-year-olds ranged from 70% to 93%; referral rates were 1% to 41%, and follow-up rates were 29% to 100%. Successful screening among 4-year-olds ranged from 88% to 98%; referral rates were 2% to 40%, and follow-up rates were 41% to 100%. The proportion of 3-year-olds who were treated was significantly different between the community-based sites (n ϭ 20) and the primary care sites (n ϭ 2). Similarly, the proportion of 4-year-olds who were treated was significantly different between the community-based sites (n ϭ 36) and the primary care sites (n ϭ 11).CONCLUSIONS. The variability across pilot sites in numbers successfully screened and numbers referred suggests that all aspects of preschool vision screening need thorough review before the goal of universal preschool vision screening can be realized. 5 In a joint policy statement with the AAO, the AAPOS, and the American Association of Certified Orthoptists, the AAP recommended that physical inspection of eye functioning and overall eye health begin at birth and that "objective evaluation" of acuity be initiated by 3 years of age. 6 As many as 34 states have endorsed programs for vision screening to improve the rates of preschool vision screening. 7,8 However, there is state-to-state variability regarding whether the programs are mandated, as well as how they are implemented. In addition, studies in primary care settings indicate that few preschool-aged children are screened for vision problems. [9][10][11] In 1998, the Maternal and Child Health Bureau (MCHB), Health Resources and Services Administration (HRSA), collaborated with the National Eye Institute (NEI), National Institutes of Health (NIH), and various national and state agencies to review research and policies related to vision screening in preschool-aged children. The specific mission was to determine "useful screens to efficiently detect amblyopia risk factors and other significant problems" and "to provide and evaluate the practicality and effectiveness of ocular screening services for young children, including photoscreening technology." An expert panel, the MCHB/NEI Preschool Vision Screening Task Force, was convened in Septem...