Effect of a Topical Antibiotic and Povidone-Iodine Versus Povidone Iodine Alone on Conjunctival Flora: A Systematic Review and Meta-Analysis.

Topic: This systematic review and meta-analysis aimed to determine whether adding preoperative topical antibiotics to povidone-iodine (PVI) offers any additional benefit over PVI alone in reducing conjunctival bacterial flora, thereby potentially lowering the risk of postoperative endophthalmitis. The participants included 1423 eyes undergoing elective intraocular surgeries (e.g., cataract, keratoplasty, trabeculectomy) or receiving intravitreal injections. The interventions studied were PVI combined with third-generation quinolones (levofloxacin, moxifloxacin, or gatifloxacin) compared with PVI alone. The outcome measure was post-intervention rate of positive conjunctival bacterial cultures prior to ophthalmic procedure.

Clinical relevance: Postoperative endophthalmitis is a rare but serious complication of intraocular surgery, potentially leading to significant vision loss. While PVI is widely recognised as an essential prophylactic measure, the role of preoperative topical antibiotics remains debated. Defining the necessity of antibiotic use in routine cataract surgery is important, especially given the concerns about antibiotic resistance and the rising cost of healthcare. The current standard of care varies globally, with PVI commonly used alone in many regions, such as the UK.

Methods: Studies were included based on the comparison of preoperative PVI with or without antibiotics in patients undergoing intraocular surgery. Searches were conducted in PubMed, Cochrane, and Embase databases, covering literature up to October 2024. Risk of bias was assessed using the Cochrane risk of bias tool.

Results: Seven studies were included, comprising 1423 eyes. A meta-analysis revealed no significant difference in the reduction of conjunctival bacterial flora between PVI + antibiotics and PVI alone (OR: 0.77, 95% CI 0.42-1.42, p=0.41). Subgroup analysis showed that levofloxacin combined with PVI significantly reduced positive culture rates (OR: 0.48, 95% CI 0.29-0.81, p=0.006), while moxifloxacin and gatifloxacin did not show similar benefits. Moderate heterogeneity was observed across studies (I2=58%, p=0.04).

Conclusion: This review found no conclusive benefit of using preoperative topical antibiotics alongside PVI in routine ophthalmic procedures. However, in patients at high-risk of endophthalmitis, levofloxacin may offer additional protection.