Global inequality in disability-adjusted life years due to eye diseases: a cross-national analysis from 1990 through 2015

PurposeThe aim of this study was to evaluate the trends in global inequality in eye health by using data on the global burden of disease measured in disability-adjusted life years (DALYs). MethodsThis is an international observational study. We estimated the burden of eye disease by calculating the sum of DALYs (from the Global Burden of Disease study, 2016 update) due to cataract, refraction and accommodation disorders (RE), glaucoma, age-related macular degeneration (AMD), and other causes. We assessed the burden of various eye disease in relation to economic status and etiology by calculating the Gini coefficient, and the concentration index. ResultsThis study included 195 countries, VI accounted for 2.46 (95%CI: 2.26 to 2.70) billion DALYs. Global inequality in the health burden due to VI has not changed greatly in the last 25 years, with a Gini coefficient of 0.217 in 1990 and 0.201 in 2015 Cataract was concentrated in poor socioeconomic countries, while AMD was concentrated in higher socioeconomic countries. In 1990, cataract was the most unevenly distributed cause, followed by AMD, RE, glaucoma, and other causes. In 2015, cataract remained the most unevenly distributed cause on a global scale, followed by RE, AMD, glaucoma, and other causes. Time trends of inequality in high-income economies differed from those in low- and middle-income economies. There is an ongoing reduction in the inequality of the VI burden across high-income countries; however, there is an upward trend across low- and middle-income countries. The inequality of RE has improved among high-, low-, and middle-income economies. ConclusionThe health burden of eye diseases has not improved and that the global inequality of eye health has increased continuously in the last 25 years. Time trends of inequality in high-income economies differed from those in low- and middle-income economies.