Sir,

As non-wearers of surgical masks, we were interested to read the editorial by Trivedi and Wilson1 recommending the use of face-masks during cataract surgery. The immediate evidence for this recommendation was the multivariate analysis of retrospectively reported risk factors for postoperative infective endophthalmitis (PIE) from the British Ophthalmic Surveillance Unit, reported by Kamalarajah et al.2

The evidence for the use of face-masks in surgery generally is poor, with no effect on theatre air bacterial counts3 and no effect on wound infection rates in a major randomised controlled general surgical trial.4 Culture plates placed around the patient during cataract surgery without masks have been shown in one study to have increased bacterial cell counts,5 but there are no prospective studies of face-mask use and PIE. It would be surprising to find a greater effect from mask use in the prevention of PIE than pertains in general surgery, given that the majority of PIE organisms are presumed to originate from the patients' conjunctival flora.

Where the evidence for benefit is uncertain, it is appropriate to assess adverse effects. Theatre masks increase condensation on operating microscopes and may impair the surgeons' view. Masks may rub on the face, thus displacing facial skin squames onto the operative site. Unnecessary use is inconvenient, wasteful, and impairs communication. In the absence of direct evidence of harm, we consider it reasonable to continue our current practise of not wearing face-masks in theatre.