Purpose: To compare disinfection by povidone-iodine (PI) solution with that by polyvinyl alcohol-iodine (PAI) solution in preoperative eyewash and to assess the optimal duration of the preoperative application of 0.5% levofloxacin (LVFX) ophthalmic solution.
Methods: Two-hundred-seventy-two elderly cataract patients who had undergone phacoemulsification aspiration with intraocular lens insertion at 12 clinical facilities in Japan were randomized into three groups: 3-day, 1-day, and 1-h preoperative application of 0.5% LVFX ophthalmic solution. Each LVFX group was further divided into two subgroups; the patients in one subgroup were treated with diluted PI eyewash, and those in the second subgroup with diluted PAI eyewash, immediately before the surgery. Thus, a total of six groups were studied. Conjunctival scrapings were collected four times: before LVFX application, after LVFX application, after the eyewash with iodine compounds, and after the surgery. Samples of the aqueous humor were collected immediately after the surgery. All samples were cultured aerobically and anaerobically.
Results: The 3-day application of LVFX had a significantly higher disinfection rate than the 1-day or 1-h applications (P<0.05). The disinfection rate of PI was 78.0%, and that of PAI was 79.4%; PAI was not inferior to PI as a preoperative disinfectant. However, new isolates, mainly Propionibacterium acnes and Staphylococcus epidermidis, were detected after LVFX application and even after use of the eyewash with iodine compounds.
Conclusion: Three-day administration of LVFX ophthalmic solution and use of an eyewash with diluted iodine compounds is effective for preoperative disinfection. However, complete elimination of bacteria from the conjunctival sac is difficult.