Income-Related Inequalities in Vision Difficulty Among US Adults, 1999-2018.

Abstract

Research has shown that the prevalence of vision difficulty is higher among US adults with low income than among those with higher income. We aimed to examine the trends in income-related inequalities in vision difficulty and to identify the contributions of explanatory factors. A cross-sectional and trend study. Our study estimated income-related inequalities in self-reported vision difficulty among US adults aged 18 years or older using data from the National Health Interview Survey (NHIS) during 1999-2018. The concentration index was used to measure income-related inequality in vision difficulty and was decomposed into contributing factors. We examined temporal changes in income-related vision difficulty inequalities and contributors to those changes from 1999 to 2018. We found that vision difficulty was concentrated among lower income groups and the degree of income-related inequality in vision difficulty widened between 1999 and 2018. Decomposition analysis revealed that poverty-to-income ratio and public health insurance coverage were important contributors to income-related inequalities in vision difficulty, with smaller contributions made by smoking, physical inactivity, and female sex. Among all variables, non-White race/ethnicity, lower physical activity, and poverty-to-income ratio were important factors explaining the change in income-related inequality in vision difficulty. Vision difficulty was more prevalent in low-income populations. Our study enhances the understanding of socioeconomic disparities in vision difficulty, which could inform how to best target the deployment of eye care resources to maximize the visual potential of the US population.