Statistical Analyses

For statistical analysis of quantitative features, each eye was considered a unique observation for subjects with images of both eyes. We employed χ² tests to evaluate the distribution of sex and hypertension among various groups. To assess the normality of age and diabetes duration distribution in different groups as presented with mean and standard deviation in Table 1, we conducted the Shapiro–Wilk test. Comparisons of age and diabetes duration distribution were carried out using analysis of variance (ANOVA). In all comparisons, statistical significance was determined with a P < 0.05.