Statistical analyses
The results were expressed as median (25–75thpercentiles) since most indices followed a non-normal distribution. Comparisons between the visits were performed using Wilcoxon signed-rank test. Correlations were evaluated using Pearson’s correlation coefficient. A p value <0.05 was deemed significant. All statistical analyses were performed with StatView 5.0 software (SAS Institute, Cary, NC, United States).