Chlorhexidine Compared with Povidone-Iodine in Intravitreal Injection: A Systematic Review and Meta-Analysis

Introduction: Povidone-iodine (PI) is the standard antiseptic for intravitreal injections (IVIs), while chlorhexidine (CHX) is a potential alternative. The efficacy of PI versus CHX in preventing endophthalmitis remains debated, with studies showing mixed results. Objective: To compare the effectiveness of using PI compared with CHX in IVI procedures regarding endophthalmitis rates, culture-positive endophthalmitis rates, and changes in visual acuity. Methods: A systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. We searched the PubMed, EMBASE, Cochrane, and Web of Science databases for studies using PI compared with CHX in the IVI procedure. Statistical analysis was done using R software. Results: Four studies encompassing 453,340 eyes were included. The pooled results showed no statistical differences in endophthalmitis rates [odds ratio (OR): 1.26; 95% confidence interval (CI): 0.53-3.00]. In those who received the CHX group, there was no decrease in the rates of culture-positive endophthalmitis (OR: 2.04; 95% CI: 0.76-5.47), and the pooled results revealed no statistical differences in the mean change in visual acuity between the CHX and PI groups at final follow-up [mean difference: -0.02; 95% CI: -0.40 to 0.36]. Significant heterogeneity was identified in the post-procedure endophthalmitis rate and culture-positive endophthalmitis rate. Conclusions: Despite finding a trend toward higher rates of endophthalmitis with CHX, there are no statistical differences in using PI compared with CHX. However, our results are limited due to high heterogeneity. PI remains the gold standard, and a widespread shift to CHX cannot be justified based on the findings of this analysis.