We appreciate the comments by Drs Kahn and Rahman and agree that interpreting retrospective data must always be approached with caution.1 Indeed, properly controlled randomised prospective studies remain the gold standard for evaluating medical treatments. However, retrospective case series often provide important insights into therapies that are less commonly performed, or subject to variability in operator or technique, as is the case when comparing surgical methods. Retrospective studies also generate important preliminary data to help guide the design of future randomised trials.

Our study was devised to compare simultaneous combined phacoemulsification, PCIOL placement, pars plana vitrectomy and epiretinal membrane (ERM) peeling, with vitrectomy and membrane peeling alone.2 Patients in the membrane peeling alone group were either phakic or pseudophakic at the time of surgery. The inherent limitation of evaluating combined surgeries …