Post- intravitreal injection endophthalmitis pattern during the COVID-19 pandemic with implementation of patient masking

Purpose: To evaluate the role of patient facial mask on the occurrence of post- intravitreal injection (IVI) endophthalmitis in a real word setting. Design: Retrospective cohort. Participants: Patients receiving IVIs between 20 February 2019 and 20 February 2021; a 12-month period before the official beginning of COVID-19 epidemic in Iran and a 12-month period after that. Intervention: In the pre-COVID era patients underwent IVI without a facial mask while in the COVID era patients were treated with an untapped facial mask. Physicians and staff had facial mask in both periods. IVIs were administered in a dedicated operating room and no strict talk policy was followed. Main outcome measure: The rate of post- IVI endophthalmitis. Results: A total number of 53927 injections was performed during the study period: 34277 in pre-COVID and 19650 in COVID periods; with a 42.7 % decrease in the number of injections. The endophthalmitis occurred in 7 eyes (0.02%) in pre-COVID and 7 eyes (0.03%) in COVID era (p=0.40). In multivariate analysis, after adjustment for intercorrelations between eyes and multiple injections in one patient, there was no statistically significant association between wearing facial masks by the patients and risk of endophthalmitis (relative risk= 1.47, 95% confidence interval of 0.97-2.22; p=0.071). Conclusion: Patient facial masking is probably not associated with increased risk of post- injection endophthalmitis.