This study was performed to compare the effect of fourth-generation fluoroquinolones gatifloxacin on epithelial healing and penetration into the aqueous humor following corneal epithelial removal. The administered drugs were Zymar™ and Gatiflo®, which differ from each other by the presence of benzalkonium chloride.

Eighteen eyes of nine New Zealand white rabbits were randomized to receive either Zymar™ or Gatiflo® following anterior keratectomy with a diameter of 6.0 mm. Eyes were dosed with either antibiotic according to Food and Drug Administration (FDA) approval; specifically, Zymar™ and Gatiflo® were dosed every two hours for the first two days and then four times daily for the following five days. Starting from postoperative day 0, photos were taken daily to measure the area of the residual epithelial defects. Anterior chamber paracentesis was performed to determine the drug concentration at postoperative days 1, 2, and 7.

The mean healing times after Zymar™ and Gatiflo® treatment were 3.0±0.71 and 3.2±0.84 days, respectively ( P =0.813). No statistically significant differences in the mean healing time and the mean area of the healed corneal wound were noted between the two groups. No difference in anterior chamber concentration was observed between the two groups at postoperative day 7 ( P =0.362).

Although the two drugs differ in that on drug has preservatives, no significant differences were found in the epithelial healing effect or anterior chamber concentration after short-term dosing for 1 week in this trial.