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

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.

Tertiary ophthalmic referral center, Munich, Germany.

Prospective comparative case series.

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.

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.

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.

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