The night vision threshold test (NVTT): A simple instrument for testing dark adaptation in young children

It is estimated that 41 per cent of the population aged under 5 in the deve loping world has an inadequate vitamin A dietary intake resulting in increa sed morbidity and mortality. Half a million children go blind each year as a result of vitamin A deficiency. Thirteen and a half million have night bl indness, the first sign of vitamin A deficiency. Unfortunately, there is no simple, sensitive and inexpensive means to identify the child who has marg inal levels of vitamin A and thus institute means to prevent their developm ent of severe deficiency, A low cost, simple, easy-to-use instrument design ed to detect a young child's ability to adapt to darkness was tested in chi ldren admitted to the Mwanamugimu Nutrition Unit at Makerere Medical School in Kampala, Uganda, Despite the severe degree of malnutrition found in the se children, Night Vision Threshold Test results and serum retinol levels w ere related (r = 0.41, p < 0.05), Further efficacy trials for this instrume nt are planned at community sites in Nepal.