Although the extent of VAD in a country is generally captured by prevalence rates, merely counting the number of people below a certain threshold for VA sufficiency fails to take account of the problem’s depth. Disability-adjusted life years (DALYs) provide a means to measure the total disease burden in one single index. This is done by weighting different health
conditions (including premature death) according to their severity and adding up their duration. 1 DALYs were first used in the ‘‘World Development Report 1993’’