The variability of vision loss assessment in federally sponsored surveys: seeking conceptual clarity and comparability.

PURPOSE To review U.S. national population-based surveys to evaluate comparability and conceptual clarity of vision measures. DESIGN Perspective. METHODS The vision questions in 12 surveys were mapped to the World Health Organization's International Classification of Functioning, Disability and Health framework under the domains of condition, impairment, activity limitation, participation, and environment. Surveys examined include the National Health Interview Survey, the Behavioral Risk Factor Surveillance Survey, National Health and Nutrition Examination Survey, the Census, and the Visual Function Questionnaire. RESULTS Nearly 100 vision measures were identified in 12 surveys. These surveys provided no consistent measure of vision or vision impairment. Survey questions asked about differing characteristics of vision-related disease, function, and social roles. A question related to ability to read newspaper print was the most commonly asked question in surveys. CONCLUSIONS Limited comparability of data and lack of conceptual clarity in the population-based surveys resulted in an inability to consistently characterize the population of people experiencing vision impairment. Consequently, vision surveillance was limited.