Application of a rapid dark adaptation test in children

The rapid dark adaptation test (after Thornton) has been shown to correlate with classical dark adaptation test results and vitamin A nutriture in adults. Using this test, 27 children in Guatemala (aged 5-12 years) and 18 children in Baltimore (aged 4 and 5 years) were studied. Plasma for vitamin A and zinc analysis was obtained from the Guatemalan children and dietary histories were obtained from the parents of the Baltimore children. All but two children (ages 4 and 5) were able to complete the study. For the Guatemalan group, the mean time to complete the test was 144 s, and for the Baltimore group, 171 s. Rapid dark adaptation test performance was significantly correlated to the dietary intake of vitamin A by a logarithmic model, p less than 0.05. The rapid dark adaptation test appears to be acceptable for use in childhood populations and could complement biochemical determination of vitamin A and/or zinc in clinical settings, field surveys, and research.