No increase in incidence of post-intravitreal injection endophthalmitis without topical antibiotics: a prospective...

In our previous report, intravitreal injection using 0.25% povidone-iodine to irrigate the conjunctival sac together with pre- and post-injection topical antibiotics achieved an incidence of post-injection endophthalmitis significantly lower than other reports. In this study, we examined whether similarly low incidence is achieved without using any topical antibiotics.

Prospective cohort study.

We evaluated intravitreal injections of anti-vascular endothelial growth factor agents conducted by vitreoretinal specialists at the outpatient injection room of a single university hospital. This study had two protocols. First stage: We performed more than 3000 injections with pre-injection but without post-injection topical antibiotics. Final stage: After confirming no case of endophthalmitis in the first stage, we performed more than 12,500 injections without either pre- or post-injection topical antibiotics. In both protocols, we used 0.25% povidone-iodine to sterilize the conjunctival sac both before and after injection.

First stage was performed between April 2015 and January 2016. No case of suspected or proven infectious endophthalmitis occurred in 6039 injections [95% confidence interval (CI) 0-0.000497%]. Final stage was performed between February 2016 and November 2017. No case of suspected or proven infectious endophthalmitis occurred in 12,523 injections (95% CI 0-0.00024%). This result was comparable to our previous study using both pre- and post-injection topical antibiotics (0/15,144 injections, 95% CI 0-0.000198%).

Using conjunctival sac irrigation with 0.25% povidone-iodine before and after intravitreal injection, the incidence of endophthalmitis remains low even when the use of pre- or post-injection topical antibiotics is discontinued.