Data analysis
All statistical analyses were performed using IBM SPSS Statistics version 22 (IBM Corp, Armonk, NY, USA). The normality of the data was tested by the Kolmogorov–Smirnov test, which showed that none of the variables except age followed a normal distribution. Categorical variables were compared using the chi-square test. Continuous variables were analysed using the Mann–Whitney U test. Changes in BCVA at various time points compared to baseline were tested using the Wilcoxon signed-rank test. Statistical significance was defined as 