The effect of contact lens hygiene behavior on lens case contamination

To assess the association between the levels of lens case contamination and lens wearers' hygiene behaviors.

Contact lens wearers were surveyed for information on wearer demographics and contact lens hygiene behavior. Microbial analysis of lens cases was performed. Multivariate analysis was used to identify factors associated with contact lens storage case contamination.

One hundred nineteen contact lens wearers responded. The mean (±SD) age of the participant was 32 (±1) years (range, 18 to 69 years). Seventy percent of the participants were female. Sixty-six percent of lens cases were contaminated (median, 25; range, 0 to 10⁷ colony-forming units [CFUs]). In the multivariate analysis, washing hands with soap and water (1.8 ± 2.0 log10 CFU/case) rather than just water or no washing was associated with lower levels of lens case contamination (2.4 ± 2.1 log10 CFU/case; p = 0.005). Lens cases received wet had higher levels of contamination than dry cases (1.5 ± 1.5 vs. 2.4 ± 2.5 log10 CFU/case; p = 0.015). Mismatching lens case and disinfecting solution was a risk factor for lens case contamination (p = 0.019). Lens wearers who had more than 2 years of wearing experience had higher levels of contamination than those who had less than 2 years of wearing experience (2.1 ± 2.1 vs. 1.1 ± 1.5 log10 CFU/case; p = 0.04).

Major factors that can reduce lens case contamination were washing hands with soap and water, air-drying lens cases, and matching of the disinfecting solution with lens case (i.e., from the same manufacturer). This information is beneficial when advising lens wearers in clinical practice.