Prospective randomised comparison of external dacryocystorhinostomy with and without silicone intubation: considerations of power

We read with interest the article by Saiju et al 1 on a randomised trial comparing the success of dacryocystorhinostomy (DCR) with and without silicone intubation. The authors concluded that there was no statistically significant difference between the two groups and that their study did not support the routine use of silicone tubes. However, we are concerned that the study did not recruit sufficient patients to reach statistical significance. When a study fails to demonstrate a statistically significant difference, this can be for one of two reasons: (1) that there really is no difference in the wider population between the two arms of the study or (2) that there may be a difference, but insufficient patients were recruited to demonstrate this. …