Sample size
This study was expected to enroll 75 patients in each of the 2 treatment arms, for a total of 150 randomized patients. Assuming a 10% dropout rate, 67 patients per group were expected to complete the study. Assuming a common standard deviation (SD) in the change from baseline for the pre-CAE to post-CAE change in inferior corneal fluorescein staining of 0.80 U, a sample size of 67 patients per treatment group could detect a mean difference of 0.39 U between the active treatment group and the placebo group at a significance level of 0.05 with 80% power. A sample size of 67 patients per treatment group could detect a mean difference of 0.49 U in the change from baseline for the pre-CAE ocular discomfort as assessed by the Ora Calibra Ocular Discomfort Scale with 80% power, assuming an SD of 1.00 U. The power for both the sign and symptom endpoints was 64%, assuming independence between the endpoints. Although sample size calculations were based on completed patients, primary analysis for sign and symptom primary endpoints were conducted on the ITT population using Markov chain Monte Carlo imputation.