Background/aims: To evaluate microbial contamination of multiply used preservative-free artificial tears packed in reclosable containers after daily use.
Methods: Subjects were provided with preservative-free artificial tears (Group 1 and 2) and artificial tears containing a preservative (Group 3). After administration three times or more per ten hours, bottles were collected and any remaining fluid in the bottles was cultured. Risk factor analysis for microbial contamination was performed by the use of univariate and multivariate analysis.
Results: A total of 242 eye drop bottles were evaluated. Five (2.0 %) of the 242 bottles had bacterial contamination. In group 1, four (3.9 %) of 102 bottles were contaminated and identified bacteria were all coagulase-negative Staphylococcus. In group 2, one (1.0%) of 105 bottles was contaminated and it was a gram negative Acinetobacter species. No bottles from group 3 showed contamination. Based on multivariate analysis, advanced age and fingertip touch were statistically significant risk factors for microbial contamination (p <0.05).
Conclusion: Preservative-free artificial tears in reclosable containers are at risk of contamination in a daily and multiple use setting, especially in patients with poor administering technique, which is associated with fingertip touch and advanced age.