Comparison of 1-day versus 1-hour application of topical neomycin/polymyxin-B before cataract surgery

Abstract

Purpose: To compare the efficacy of 2 prophylaxis regimens before cataract surgery using topical antibiotics (1 hour before surgery versus the day before), both with povidone-iodine, with regard to reducing the preoperative conjunctival bacterial load.

Setting: Tertiary ophthalmic referral center, Munich, Germany.

Design: Prospective comparative case series.

Methods: Eyes were treated with topical antibiotics and their conjunctival sac flush irrigated using 10 mL of povidone-iodine 1.0%. All eyes were randomized to receive either 4 applications of topical 3500 IU/mL neomycin sulfate/6000 IU/mL polymyxin-B sulfate within 1 hour preoperatively (Group 1) or on the day before surgery (Group 2). Conjunctival specimens were obtained at 4 timepoints: T0C untreated fellow eye (control), T0 surgery eye (after antibiotic prophylaxis but before povidone-iodine irrigation), T1 after povidone-iodine, and T2 at the conclusion of surgery. All specimens were inoculated onto blood and chocolate-blood agar and into thioglycollate broth.

Results: One hundred thirty-three eyes of 133 consecutive patients were included (Group 1, 64 eyes; Group 2, 69 eyes). The antibiotic regimens were equally effective in reducing the aerobic and microaerophilic conjunctival flora (Group 1, P=.028; Group 2, P=.000), but had no significant effect on anaerobic bacteria (Group 1, P=.201; Group 2, P=.117). Flush irrigation of the conjunctival sac using 10.0 mL povidone-iodine 1.0% significantly decreased the conjunctival bacterial load in both groups.

Conclusion: Topical neomycin/polymyxin-B was equally effective in reducing the conjunctival bacterial load whether given 1 day or 1 hour before surgery. The greatest effect was achieved by irrigating the conjunctival sac using povidone-iodine.

Financial disclosure: No author has a financial or proprietary interest in any material or method mentioned.