Rates of post-injection endophthalmitis with 5% vs. 10% povidone-iodine preparation

Abstract

Purpose : Endophthalmitis is a rare but devastating complication of intravitreal injections. Sterile povidone-iodine preparation prior to injection is considered to be critical in preventing post-injection endophthalmitis, although it is unknown whether a higher 10% concentration of povidone-iodine may be superior to 5% povidone-iodine preparation. The goal of this study was to evaluate rates of endophthalmitis in patients undergoing intravitreal injections who were prepped with 5% versus 10% povidone-iodine.

Methods : This was a retrospective study in a private practice setting evaluating all patients who received intravitreal injections of bevacizumab, aflibercept, ranibizumab, and triamcinolone acetonide between August 2015 and October 2017. The type of povidone-iodine preparation (5% vs. 10%) was recorded, and the primary outcome was post-injection endophthalmitis. Patients who received intravitreal Kenalog® were excluded given reports of post-Kenalog® injection related inflammation mimicking endophthalmitis. Results were analyzed using Stata 13.1 with Pearson’s chi-squared test.

Results : A total of 49,967 patients underwent intravitreal injection during this time period, 35,987 (72.0%) of which were prepped with 5% povidone-iodine and 13,980 (28.0%) of which were prepped with 10% povidone-iodine. There were 17 cases of post-injection endophthalmitis, 14 of which were in the 5% povidone-iodine group and 3 of which were in the 10% povidone-iodine group. The rate of endophthalmitis in the 5% povidone-iodine group was 0.04% and the rate of endophthalmitis in the 10% povidone-iodine group was 0.02%. This difference was not statistically significant (p = 0.343).

Conclusions : While there have been reports to suggest that 10% povidone-iodine may be more effective than 5% povidone-iodine in reducing conjunctival bacterial load prior to cataract surgery, this has not been evaluated in the setting of intravitreal injections. Our study did not find a significant difference in the rate of post-injection endophthalmitis with 5% vs. 10% povidone-iodine preparation prior to intravitreal injection. This difference may be difficult to detect due to the relative rarity of post-injection endophthalmitis and may warrant further study with larger samples of patients undergoing intravitreal injections.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.