From the American Academy of Ophthalmology

This prospective study compared the efficacy of topical neomycin/polymyxin-B given 1 hour or 1 day before surgery. Subjects included 133 consecutive patients randomized across the 2 regimens. In both groups, the conjunctival sac was irrigated with 10.0 mL of povidone-iodine 1.0% solution. The authors found that same-day prophylaxis was as effective as medication given the day before surgery. Regardless of the regimen used, povidone-iodine was the most effective measure in reducing the preoperative conjunctival bacterial load. Journal of Cataract & Refractive Surgery, April 2015