Screening Preschoolers for Vision Disorders
In September, 1998 the Health Resources and Services Administration's Maternal and Child Health Bureau (MCHB) and the National Eye Institute (NEI) convened an expert panel to review the state-of-the-art of preschool vision screening. The expert panel was composed of pediatric ophthalmologists and optometrists, pediatricians, vision scientists, and representatives from organizations concerned with vision screening in children. Their dedication to advancing preschool vision screening was fueled by the recognition that good vision is integral to a child's lifetime health and that early detection of vision problems are thought to lead to better outcomes.
At the time of the expert panel meeting, a number of professional organizations in the United States had published policy statements advocating early vision screening along with screening guidelines. Various types of screening programs for preschool children were being implemented, but concerns remained about the scientific validity and effectiveness of these programs. Key among these concerns was to determine the best diagnostic tools and testing protocols for vision screening and to determine which age groups should be targeted.
The full meeting proceedings were published by the Department of Health and Human Services (HHS) and a summary report appeared in the journal Pediatrics in the November 2000 issue. The publications energized the preschool vision research community. One group of investigators, who had been awarded a NEI planning grant in 1996, stepped up its efforts to comprehensively evaluate preschool vision screening tests. In 2000, the Vision in Preschoolers (VIP) Study group was funded by the NEI to conduct a multi-phased, multi-center, interdisciplinary, study designed to determine whether there are tests or a combination of tests that can effectively identify preschoolers in need of a comprehensive eye exam. Phase I of the VIP study was conducted over a two-year period during which time more than 2,500 high risk preschoolers were screened for vision disorders. Optometrists and ophthalmologists experienced in working with children administered 11 commonly used screening tests. Test results were compared to findings from comprehensive eye exams to establish their sensitivity for detecting vision disorders. The primary VIP Phase I outcome paper was published in the journal Ophthalmology in April, 2004 and was selected as the 2004 Editors' Choice award. Results showed that approximately 98 percent of 3- to 5-year-old participants could be screened successfully-an important consideration when testing preschoolers. But even in the hands of licensed eye care professionals, under controlled circumstances, the accuracy of the screening tests varied widely. In fact, a number of commonly used screening tests performed poorly. However, others performed rather well. These results provide the most comprehensive scientific evidence for evaluating preschool vision screening tests and are relevant to the professional, governmental, and private organizations concerned with children's vision.
Phase II of the VIP study was designed to assess the performance of less-skilled personnel in administering the best preschool vision screening tests as established in Phase I. Fifteen hundred high risk children were screened in typical screening environments by pediatric nurses and lay screeners. Comparison of screening results to findings from a comprehensive eye examination indicated that specially trained nurses and lay people can achieve results that are comparable to screenings performed by licensed eye care professionals. VIP Phase II results were published in the August 2005 issue of Investigative Ophthalmology and Visual Science and provide scientific evidence that non-professionals can perform select tests with good accuracy.
While the results of VIP Phase I and II provide rigorous data with regard to some aspects of preschool vision screening, key issues remain to be addressed. Anecdotal reports indicate that only a fraction of U.S. children who fail a screening exam go on to receive a comprehensive eye exam and needed treatment. Thus, keen interest lies in research designed to maximize screening follow-up. And while there is scientific evidence from a small number of studies conducted outside the U.S. indicating that preschool vision screening reduces the prevalence of vision disorders among school-age children, there is little evidence quantifying screening's impact on children's educational achievement and functional status. NEI will continue to support high quality studies to address these issues.
Posted: February 2011