2.4. Sample size calculation
According to the preliminary clinical trial, the total effective rate of MT combined with sodium hyaluronate was 93.4%, and that of sodium hyaluronate was 66.6%. Use PASS15.0 to estimate the sample size, adopt a superiority design, in which α = 0.05, β = 0.2, test power = 0.8, number of cases in experimental group: number of cases in control group = 1:1, boundary value = –0.4. According to the software calculation, the total sample size of the 2 groups was 110 cases. Taking into account the clinical shedding rate of about 10%, a total of 120 cases will be finally included. The included patients will be numbered according to the order of treatment and divided into the treatment group and the control group by completely random method, with 60 cases in each group.