Disability Adjusted Life Years (DALYs)
Disability adjusted life years (DALYs) provide a measurement of the personal burden of health conditions. DALYs are the most commonly cited measure of patient disability or well-being internationally. The 2010 Global Burden of Disease Study conducted a multi-country survey of approximately 20,000 households to estimate disability weights for 220 unique health states and conditions, including visual impairment and blindness. Disability weights related to vision are listed in Table 14.1. International definitions for severe impairment includes distance acuity of 20/200 or worse in the better-seeing eye, which is the U.S. based threshold for blindness used in this analysis. We therefor averaged the disability weights for severe impairment and blindness (0.193) to determine the disability weight applied to the U.S. defined blindness population in our study.
Table 14.1. Disability Weights from 2010 Global Burden of Disease Project
We estimated total DALY losses by multiplying the disability weights by the prevalent population with the corresponding level of vision loss. As the disability weights were measured controlling for other conditions, we did not adjust the disability losses based on any assumed background disability weights. We find a total loss of 283,000 DALYs. DALYs are not intended to be monetized, nonetheless using a commonly cited value for utility or disability weighted life years of $50,000, monetizing the DALY losses would indicate a loss of $14.2 billion.