Rates of endophthalmitis before and after transition from povidone-iodine to aqueous chlorhexidine asepsis for intravitreal injection

Objective To assess the rate of post-intravitreal injection endophthalmitis between 2 asepsis groups: aqueous chlorhexidine 0.1% and povidone-iodine 5%. Design Retrospective, observational cohort study. Participants Patients with infectious endophthalmitis post intravitreal injection (n = 58) at a single centre from July 2009 to July 2022. Methods Retrospective chart review of all patients receiving intravitreal injections (216 593 injections) at a single centre over 14 years. Patients from July 2009 to February 2017 received povidone-iodine 5%, and patients from March 2017 to July 2022 received aqueous chlorhexidine 0.1%. Assessed characteristics of endophthalmitis cases included demographics, visual function, intervention type, and microbiological results. Results The rate of endophthalmitis was comparable for povidone-iodine (1.4:5000) and aqueous chlorhexidine (1.3:5000) (p = 0.77). Vitreous cultures were negative for 55% of patients. Visual acuity (VA) outcomes did not differ between asepsis groups nor between culture positive/negative groups. Patients having vitrectomy (PPV) had worse final vision (p = 0.08) but there was no VA difference between early and late PPV. Conclusions Aqueous chlorhexidine 0.1% is a viable and safe alternative to povidone-iodine 5% for post-intravitreal injection endophthalmitis prophylaxis and may reduce ocular surface adverse events and discomfort.