Effect of chronic topical glaucoma medications on aerobic conjunctival bacterial flora.

PURPOSE: To investigate whether the chronic topical medications affect aerobic conjunctival bacterial flora of patients with glaucoma and to compare their findings with the findings of the controls. METHODS: Eighty-one patients and 67 healthy control subjects participated in this case-control study. Duplicate conjunctival swab specimens were collected from each patient at the microbiology laboratory and were investigated for the presence of aerobic bacteria. All bacterial species from isolated colonies were identified. RESULTS: Thirty seven (45.7%) of the 81 patients and 25 (37.3%) of 67 controls had positive conjunctival cultures. Coagulase-negative Staphylococcus was the most commonly isolated bacterial species in both groups. There were no statistically significant differences between the prevalence of other conjunctival cultures testing positive for any of the isolated organisms. The patients were also evaluated with respect to the presence of a systemic illness. Age, sex, presence of diabetes and asthma, duration of antiglaucomatous medication, and number of medications used did not have an effect on culture positivity in both groups when evaluated by logistic regression model. CONCLUSIONS: The conjunctival culture positivity was higher in patients with glaucoma than in the healthy controls and in patients with diabetes than in patients without diabetes, although both were statistically insignificant. Aerobic conjunctival flora of the patients using topical glaucoma medications and the controls did not differ. Further studies are needed to comment on the clinical importance of these findings.