Decomposition of Economic Inequality in Cataract Surgery Using Oaxaca Blinder Decomposition: Tehran Geriatric Eye Study (TGES)

Abstract

ABSTRACT Purpose The aim of this study was to investigate economic inequality in cataract surgery and to decompose it into its determinants using Oaxaca-Blinder decomposition. Methods The Tehran Geriatric Eye Study is a population-based cross-sjal study that was done on individuals above 60 years using stratified cluster random sampling. All subjects underwent full optometric, slit lamp, and fundoscopic examinations. Then, after pupil dilation, the history of cataract surgery, including PC and AC IOL, was determined. Results The age and sex-standardized prevalence of cataract surgery was 33.51% (95% CI: 31.45 to 35.62). Cataract surgery had a significant positive association with age (OR: 14.06; p < .001 for >80 vs 60–64 years) and a significant inverse association with education level (OR: 0.55, p: 0.006 for college education vs being illiterate) and economic status (OR: 0.64, p: 0.003 for rich vs poor). A significant difference was found in cataract surgery between the rich and poor (26.22%) disfavoring the poor (p < .001). The explained and unexplained portions comprised 95.99% and 4.01% of the difference (p < .001 and p = .336, respectively). Among study variables, age (p < .001), education (p = .003), economic status (p = .002), insurance (p = .011), and eye examination (p < .001) were significant determinants of inequality in the explained portion. Conclusion There was a marked difference in the prevalence of cataract surgery between the rich and poor that was mostly caused by the explained portion. Age, economic status, and education had the largest effects on increasing the inequality and history of eye examination by an ophthalmologist and insurance coverage had the largest effects on reducing this inequality.