Impact of Prefilled Syringes and Masking on Postintravitreal Injection Endophthalmitis

Purpose: To compare rates of endophthalmitis (1) following intravitreal injection of antivascular endothelial growth factor therapies with glass-vial preparation (GVP) vs prefilled syringes (PFS) and (2) before and after masking protocols were implemented. Methods: Medical records within a multicenter retina practice in Houston, Texas, from January 2015 to August 2021 were retrospectively reviewed. The primary outcome was rate of endophthalmitis after intravitreal injection. Results: A total of 307 349 injections were performed during the study period and 101 cases of endophthalmitis were identified (0.033%). PFS use was associated with a decreased risk of endophthalmitis (relative risk [RR], 0.320; 95% CI, 0.198-0.518, P < .001); 54 cases of endophthalmitis occurred in the GVP group of aflibercept and ranibizumab (0.052%) compared with 24 in the PFS group (0.017%). There was no difference in the endophthalmitis rates with or without universal masking (RR, 0.953; 95% CI 0.616-1.473, P = .91). Discussion: PFS use was associated with a significant reduction in the rate of endophthalmitis while the use of surgical face masks did not appear to significantly impact the rate of endophthalmitis.