Purpose: To investigate the effects of topical dexamethasone and ciprofloxacin, alone and in combination, on the colony counts of conjunctival bacterial flora of healthy subjects.
Methods: A total of 100 healthy subjects were randomly divided into four groups, consisting of 25 subjects each. Group 1 was treated with dexamethasone phosphate 0.1% (Maxidex). Group 2 was treated with ciprofloxacin 0.3% (Ciloxan) and Group 3 with a combination of these drugs. Group 4 received artificial tear solution (Tears Naturale) and served as control. The drops were administered one drop every 1 min. A pretreatment culture and recultures at 30, 90, and 180 min after application of final drops were performed on all subjects. The bacterial growth was evaluated in a quantitative manner. All cultures were performed in a double-masked fashion. ANOVA test was used for statistical analyses.
Results: While there was no significant difference among mean number of pretreatment colonies between the groups (P=0.85); the differences at 30, 90, and 180 min were statistically significant (P<0.001). During the study there was no statistically significant change in colony counts in Groups 1 and 4 (P=0.66 and 0.55, respectively). The colony count numbers decreased significantly at 30 and 90 min in Group 2 (P<0.001 and P=0.004) and at 30 min in Group 3 (P=0.002).
Conclusion: Topically applied dexamethasone did not cause a significant change in colony counts of the healthy conjunctiva. Both ciprofloxacin and a combination of ciprofloxacin and dexamethasone were effective in the reduction of bacterial ocular flora.