The effect of a novel contact lens blister pack solution on bacterial contamination during lens handling

Abstract

Purpose : Contact lens handling is a significant source of lens contamination. Numerous studies have indicated that poor compliance including hand hygiene is a common problem. To minimize the lens bioburden introduced from contact lens handling during insertion, we evaluated the effect of e-poly-L-lysine (e-PL), a natural, biologically derived compound in the blister pack solution on lens microbial contamination.

Methods : A single-masked, randomized study comparing a test lens (stenfilcon A, omafilcon A, somofilcon A) packaged in blister solution with e-PL at two concentrations (25microg/mL or 100microg/mL) against an appropriate control lens (no compound), and including 1-Day Miru, was conducted. Up to 20 subjects handled each contact lens after washing their hands in a manner mimicking routine lens removal from the blister pack prior to insertion. Handled lenses were collected and evaluated for recovered bioburden. 1-Day Miru was removed from its blister pack according to the manufacturer’s instructions. All lenses were left in the recovery solution (PBS) for a total of 30 minutes prior to plating. Data were expressed as the mean of colony forming units transformed log₁₀ (+standard error) for each lens type. Log₁₀ reduction (LR) was calculated as a difference between log₁₀ control and test lens. Two-tailed Student’s t-test was used for statistical analysis.

Results : Lenses packed in the test solution at either concentration had lower microbial count than lenses packed in the control solution. Statistically significant LR was observed at the highest tested concentration of the compound (omafilcon A LR=1.7, stenfilcon A LR=1.0, somofilcon A LR=1.0, p<0.001 for all). In addition, the lowest tested concentration caused statistically significant reduction on omafilcon A (LR=1.1, p=0.0002) A smaller, but statistically significant reduction in bioburden was also found on 1-Day Miru lens compared to control omafilcon A (LR=0.8, p=0.006), control stenfilcon A (LR=0.7, p=0.02) and control somofilcon A (LR=0.8, p=0.01).

Conclusions : This pilot study demonstrated that e-PL, a novel compound in the blister pack solution, reduces bacterial contamination introduced by lens handling.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.