Spss statistics for window version 17

When comparing the baseline demographics among the three treatment groups, data is presented as frequencies, proportions, means ± standard deviations (SD), or median (minimum, maximum), according to the characteristics of each item. Some statistical tests were performed to compare the differences between groups. The chi-squared test or Fisher’s exact test was used to evaluate the association between two categorical variables. One-way analysis of variance or Kruskal–Wallis test was used to test if there were significant differences between groups. Post-hoc test was performed via Bonferroni correction. Trend analysis was adopted to evaluate the time effect on inter-eye AL difference and ΔAL. After restricting the data collection to the right eyes, the associations between risk factors and ΔAL during the follow-up period were evaluated by a generalised estimating equation (GEE). Covariates, such as treatment, intervention age, gender, follow-up time, and baseline AL, were included in the GEE model. Statistically significant differences were defined as P < 0.05. All statistical analyses were performed using SPSS Statistics for Window, version 17.0 (SPSS Inc., Chicago, IL, USA).