To report the results of a clinical comparison study of a prophylactic new generation fluoroquinolone (FQs; levofloxacin 0.5%, gatifloxacin 0.3% and moxifloxacin 0.5%) topical antibiotic regimen administered prior to intraocular microsurgery.

From May 2007 to April 2010, Trial 1, 214 eyes of 211 patients scheduled for intravitreal injection were randomized into one of three FQ-treated groups or the control (non-treated) group. Patients who were randomized into FQ-treated groups were treated with eye drops containing one of three FQ antibiotics (levofloxacin 0.5%, gatifloxacin 0.3% and moxifloxacin 0.5%) preoperatively four times a day for three days before surgery. The rate of positive bacterial cultures from conjunctival scrapings were assessed and compared. Trial 2, 159 eyes of 159 patients scheduled for cataract surgery were randomized into one of three FQ-treated groups, and treated with eye drops as same method in trial 1. The concentration of antibiotics in the anterior chamber of the eye were measured and compared.

The positive bacterial culture rates of trial 1 were 48.9%, 38.3%, 23.4% in the levofloxacin-treated group, the gatifloxacin- group, and the moxifloxacin-treated group, respectively. These rates were all significantly lower than the 70.2% positivity rate observed in the control group. Average antibiotic residue concentrations in the aqueous humor measured in trial 2 were 0.37 ± 0.49 µg/ml in the levofloxacin-treated group, 0.31 ± 0.37 µg/ml in the gatifloxacin-treated group and 0.59 ± 0.72 µg/ml in the moxifloxacin-treated group. These concentrations were not significantly different. There were no reported side effects during the study period.

Eye drops containing new generation FQ antibiotics instilled three days before microscopic ophthalmic surgery can be used safely and effectively for the prevention of postoperative endophthalmitis.