Evaluation of the Effects of Topical Ophthalmic Fluoroquinolones (FQ) on the Cornea using In Vivo Confocal Microscopy

Abstract

Abstract: : Purpose: To compare the effects of several FQ antibiotics on the corneal epithelium and stroma using in vivo confocal microscopy. Methods: Five antibiotic solutions were evaluated: 1) 0.3% ofloxacin (Oflox) solution with 0.005% benzalkonium chloride (BAC); 2) 0.3% gatifloxacin (Gati) solution with 0.005% BAC; 3) 0.3% ciprofloxacin (Cipro) solution with 0.006% BAC 4) 0.5% levofloxacin (Levo) with 0.005% BAC; 5) 0.5% moxifloxacin (Moxi) solution with no BAC. Tears Natural Free (Tears) was used as a control. New Zealand White rabbits were used for this study (six per solution group). Ten days prior to exposure to any solution, central corneal epithelial thickness (EpiTh) and stromal thickness (StrTh) were measured using in vivo confocal microscopy through focusing (CMTF). Images of the superficial epithelium were also acquired. Both eyes of each rabbit then received one drop of the assigned solution six times the first day and then qid for 6 days. On day 7, in vivo confocal microscopy was repeated. Results: A significant decrease in EpiTh (Table) was induced by 7 days of exposure to Levo, Gati, and Cipro. Tears and Moxi, which do not contain BAC, showed the smallest changes in EpiTh. Between group comparisons using ANOVA confirmed that Moxi induced smaller changes in EpiTh than Gati or Cipro. However, superficial epithelial morphology appeared normal in all groups. Interestingly, only the control group (Tears) showed a significant change in StrTh (Table). Conclusions: We have previously used confocal microscopy to establish a correlation between epithelial thinning (due to superficial cell loss) and slight ocular irritation (IOVS 39:2610-2625, 1998). The results of this study suggest that Moxi may induce less damage to the corneal epithelium than other antibiotic solutions, perhaps because it does not contain BAC.  

Keywords: antibiotics/antifungals/antiparasitics • ocular irritancy/toxicity testing • cornea: epithelium