Objective To investigate and compare the rate of endophthalmitis after intravitreal injections performed in an in-office (dedicated procedure room) versus in-theatre setting.

Methods A retrospective comparative cohort study was performed of all patients consecutively treated by a single surgeon with intravitreal injection with either ranibizimab or bevacizumab for any recognised clinical indication. All cases received injections between March 2006 and March 2012, during which time all injections were prospectively recorded on an electronic medical record system. A search of the electronic database using a report building system was used to extract the total number of injections into location-specific grouping (ie, in office vs in theatre).

Results 12 249 injections were performed over a 6-year period. 3376 of these were performed in the in-office procedure room, compared with 8873 in the operating theatre. Of the 3376 injections performed in office, there were four cases of infective endophthalmitis compared with none of the 8873 injections performed in theatre (p=0.006). In-theatre intravitreal injections were associated with a 13-fold lower risk of endophthalmitis compared to in-office injections.

Conclusions The theatre environment is a clinically appropriate location for any intravitreal injection procedures and was associated with a significantly lower risk of infective endophthalmitis in this single-surgeon comparative cohort study.