Abstract
Purpose: :
To compare the effect of gatifloxacin ophthalmic solution 0.3% (Zymar®, Allergan) with moxifloxacin 0.5% (Vigamox®, Alcon) on epithelial barrier function using pupillary dilation as a marker for loss of the barrier function of the corneal epithelium. The corneal epithelium is a barrier to penetration of pharmacologic agents into the anterior chamber. An antibiotic which breaks down the tight junctions or injures the epithelium will result in more rapid and greater dilation of the patient’s pupil than an antibiotic which does not damage the corneal epithelium.
Methods: :
Three days prior to the study 20 healthy subjects in a double masked fashion randomly received masked gatifloxacin in 1 eye and masked moxifloxacin in the other eye 4 times a day for 3 days. On the day of the study, subjects received 1 drop of each antibiotic every 15 minutes for 3 doses. Thirty minutes after the final drop of antibiotic, subjects received 1 drop of tropicamide 1% in both eyes and were asked to close their eyes for 1 minute. Digital video recordings were taken every 30 seconds until both eyes achieved maximal pupillary dilation.
Results: :
Moxifloxacin–treated eyes achieved maximum dilation significantly faster than gatifloxacin–treated eyes. Maximum dilation was reached after 8.6 (± 2.1) minutes with moxifloxacin and after 9.4 (±1.9) minutes with gatifloxacin (P=.003). In addition, the moxifloxacin treated eyes had greater pupillary dilation than gatifloxacin treated eyes, with a mean maximum pupil size of 6.9 (± 0.71) mm and 6.4 (± 0.73) mm, respectively (P=.021). There were no statistically significant differences in mean time to dilation onset (3.98 minutes with moxifloxacin versus 4.1 minutes with gatifloxacin, P=.161).
Conclusions: :
These findings suggest that moxifloxacin allows more penetration of the mydriatic agent due to damage to the epithelial barrier function than gatifloxacin. This model provides a functional evaluation of the effect of pharmaceuticals on the corneal epithelium.
Keywords: cornea: epithelium • pharmacology • antibiotics/antifungals/antiparasitics