To report the outcomes of clinical analysis on the negative culture rate of normal ocular surface flora and the anterior chamber penetration after the preoperative prophylactic use of 0.3% tosufloxacin ophthalmic solution.

From July 2010 to June 2012, 38 eyes of 38 patients who were scheduled to receive intravitreal injection or cataract surgery were examined for bacterial culture positive rate using conjunctival scraping. The patients were treated with 0.3% tosufloxacin eyedrops preoperatively 5 times a day for 2 days before surgery. After the treatment, the bacterial culture negative rate based on conjunctival scraping was assessed to evaluate the drug efficacy. Of the 38 patients, 19 had cataract surgery. The concentration of tosufloxacin at anterior chamber was assessed in the 19 patients. Additionally, any side effects from the drug were monitored during the treatment.

Among the 38 eyes, 21 eyes showed a bacterial culture positive rate before treatment. After the drug treatment, the bacterial culture negative rate was 57.1% (12/21). Coagulase-negative staphylococci were most frequently cultured in 15 (39%) of the 38 eyes before treatment and the negative rate of bacterial culture was 86.7% (13/15) after treatment. Average antibiotic residue concentrations in aqueous humor was 0.050 ± 0.038 µg/mL. No side effects from the drug were reported during the experimental period.

Although the 0.3% tosufloxacin eyedrops were not effective in all bacterial strains and showed relatively low penetration rate into the anterior chamber, they were effective in some gram positive organisms, particularly in coagulase-negative staphylococci of normal ocular surface flora.