Longitudinal changes in global cataract surgery rate inequality and associations with socioeconomic indices

Abstract

Importance: Cataract is the leading cause of blindness and the second leading cause of vision impairment. The majority of people with vision impairment reside in low-resource settings with limited access to cataract surgery and services. Background: Cataract surgery rate (CSR) is a proxy measure for eye care service delivery and estimating the burden of cataract disease. This research aims to evaluate the longitudinal changes of CSR inequality globally and by income groups. Design: Systematic review. Participants: Studies published from January 2000 to December 2015 were considered for inclusion into the review. Methods: CSR data were retrieved from a systematic review of published literature (OVID Medline, Embase, PubMed, ISI, Web of Science), unpublished reports and data repositories. Main Outcome Measures: Inequality of CSR was measured on a global scale and between countries grouped by income levels using the Gini coefficient and concentration index, with respect to the human development index (HDI). Results: Overall, correlations between HDI and gross domestic product (GDP) per capita vs CSRs were observed with R2 values of 49.2% (β = 5.01, P < 0.001) and 38.9% (β = 0.56, P < 0.001), respectively. Analysis of longitudinal CSR data using generalized estimation equation models revealed strong associations between CSR and HDI (P < 0.001), GDP (P < 0.001) and the proportion of people aged ≥50 (P = 0.001). Overall, the trend of inequality in worldwide CSR remained relatively stable. Conclusions and Relevance: Inequalities in cataract service provision were found between countries grouped by income and associated with socioeconomic indicators.