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The following is a summary of “Chlorhexidine Versus Povidone-Iodine for Intravitreal Injection Antisepsis: A Systematic Review and Meta-Analysis,” published in the March 2025 issue of American Journal of Ophthalmology by Mihalache et al. 

Researchers conducted a retrospective study to compare the efficacy and safety of chlorhexidine (CHX) and povidone-iodine (PI) for post-injection endophthalmitis (PIE) prophylaxis.  

They searched Medline, Embase, and Cochrane Library for literature published from January 2000 to July 2024. Studies comparing CHX and PI for PIE prophylaxis, functional outcomes, or safety were included. A random-effects meta-analysis was performed by the Mantel-Haenszel method for dichotomous outcomes and the inverse variance method for continuous outcomes. The primary outcome measured the incidence of PIE following CHX vs PI use, while secondary outcomes included best-corrected visual acuity (BCVA), patient intolerance, pain, safety endpoints, and cultured specimens.  

The results showed that 7 studies were included. The incidence of presumed PIE was 0.032% (n_CHX =60/185,849) with CHX and 0.026% (n_PI =69/269,491) with PI. Culture-positive PIE incidence was 0.016% (n_CHX =30/185,849) with CHX and 0.009% (n_PI =24/269,491) with PI (odds ratio (OR) =2.03, 95% CI =[0.74, 5.58], P =0.17), while culture-negative PIE was 0.016% (n_CHX =30/185,849) with CHX and 0.017% (n_PI =45/269,491) with PI (OR=0.97, 95%CI=[0.45, 2.06], P =0.93), showing no significant differences. Among 54 eyes with culture-positive endophthalmitis across 3 studies, the odds of Staphylococcus epidermidis cultures were significantly lower with CHX (n_CHX =9/30, 30.0%) than PI (n_PI =18/24, 75.0%; OR=0.15, 95%CI=[0.04, 0.54], P =0.004). No significant differences were found for Staphylococcus aureus (P =0.64), Streptococcus viridans (P =0.46), Streptococcus mitis (P =0.83), or Enterococcus faecalis (P =0.46).  The mean BCVA showed no significant difference between CHX and PI (P =0.67). The systematic review indicated minimal patient intolerance to CHX, greater pain reduction with CHX than PI, more corneal epitheliopathy with PI than CHX, and no significant difference in ocular surface microbial isolate reduction between comparators.  

Investigators concluded that CHX and PI showed statistically similar rates of presumed, culture-positive, and culture-negative PIE, and endophthalmitis cases linked to both had similar visual outcomes. Still, CHX demonstrated better safety and pain profiles and a lower likelihood of positive Staphylococcus epidermidis cultures in endophthalmitis. 

Source: ajo.com/article/S0002-9394(25)00143-6/fulltext