Decomposition of Economic Inequality in Age-Related Macular Degeneration by Using Oaxaca-Blinder Decomposition: Tehran Geriatric Eye Study.

Purpose: To investigate economic inequality in age-related macular degeneration (AMD) and decompose it into its determinants using Oaxaca-Blinder decomposition (OBD).

Methods: The Tehran Geriatric Eye Study was a cross-sectional study conducted on individuals aged 60 years and older, utilizing stratified random cluster sampling. Each participant received a comprehensive optometric, and slit-lamp examination. Diagnosis and classification of AMD were conducted utilizing fundus camera images.

Results: The data of the 3268 participants were analyzed. According to OBD, a significant difference was found in AMD between the rich and poor groups (8.36%) disfavoring the poor (p < 0.001). The explained and unexplained portions comprised 93.37% and 6.63% of the difference (p < 0.001 and p = 0.405, respectively). Among study variables, age (coefficient = 4.70; p < 0.001), economic status (coefficient = 3.58; p = 0.004), and myopia (coefficient = 0.73; p = 0.001) were significant determinants of inequality in the explained portion.

Conclusion: A significant disparity in the prevalence of AMD was observed between individuals of different socioeconomic statuses, primarily attributed to the explained factors. Factors such as age, economic status, and myopia were found to have the most substantial impact in exacerbating the inequality that disadvantaged the poor group (contributing percentages: 52.17%, 39.73%, and 8.10%, respectively). The findings of this research can be valuable for health policymakers in prioritizing and addressing the determinants of inequality within the population.