Topical Povidone Iodine 2.5% Versus 5% for Endophthalmitis Prophylaxis During Intravitreal Injections

Topical povidone iodine (PI) has been shown to reduce the risk of endophthalmitis following intravitreal injections (IVIs). However, PI is a known ocular irritant and can result in significant eye discomfort. Currently, 5% PI is the most used concentration for ocular surface disinfection prior to IVI. 2.5% PI has been proposed as an alternative IVI preparation to lessen PI-associated ocular irritation. The purpose of this study is to compare the efficacy of topical PI 2.5% to PI 5% in preventing post-IVI endophthalmitis at a single academic institution location.

A retrospective chart review was conducted at a single academic institution location of patients receiving IVI from August 1st, 2017, to June 15th, 2022. IVIs were performed using PI 2.5% or PI 5%. PI 5% was applied to the ocular surface 60 s before IVI. PI 2.5% was applied over the ocular surface and then reapplied 4-5 min later over the injection site and fornices before IVI.

A total of 7360 IVIs were performed in 773 patients (473 patients on 2.5% and 300 on 5% PI). 52.0% of IVIs were performed with 2.5% PI (n = 3826) and 48.0% were performed with 5% PI (n = 3534). The mean age of patients was 66.8 years for the 2.5% PI group and 69.1 years for the 5% PI subgroup (p=0.044). Three cases of endophthalmitis were identified in the 5% PI subgroup (0.08%), and no cases of endophthalmitis were identified in the 2.5% PI subgroup. All cases of endophthalmitis were treated with prompt intravitreal antimicrobial injection.

In this retrospective study, we found that 2.5% and 5% PI had similar results in preventing post-IVI endophthalmitis. This study adds to the literature by further supporting the antiseptic effect of 2.5% PI for IVI. Larger prospective studies are needed to further clarify the antiseptic effect and ocular surface irritation associated with 2.5% PI use.