Effect of Water Exposure on Contact Lens Storage Case Contamination in Soft Lens Wearers

SIGNIFICANCE Water exposure during contact lens wear can transfer pathogenic microorganisms to the eye, causing ocular complications. This study determined that water exposure is prevalent among lens wearers and is independently associated with higher case contamination. Contact lens compliance education to minimize water exposure should be reenforced by contact lens organizations and practitioners. PURPOSE Given the increasing association between water exposure and contact lens disease, this study aimed to explore the effect of water exposure and storage case contamination in soft contact lens users. METHODS A total of 165 daily soft lens wearers completed a self-administered questionnaire on contact lens hygiene. Lens cases were collected, and microbial analysis was conducted using an adenosine triphosphate assay (for overall microbial bioburden) and limulus amebocyte lysate assay (for endotoxin levels). The lens hygiene (excellent, >35; moderate, 28 to 35; poor, 1, poor) scores measured the compliance and water exposure during lens wear, respectively. Multiple regression determined the association between water behaviors and case contamination. RESULTS The average (standard deviation) age of participants was 28 (13.5) years (18 to 78 years), and 65% were female. The average overall microbial bioburden of storage cases was 3.10 (0.98) log colony-forming unit/mL (1.09 to 5.94 log colony-forming unit/mL). Forty-five percent of participants reported showering, 49.7% reported swimming while wearing lenses (65.4% of whom swam without goggles), 27.8% used wet hands to handle lenses, and 17.5% used tap water to rinse storage cases. Showering with lenses significantly increased the risk of higher storage case bioburden (P = .001), whereas using wet hands (P = .01) doubled the risk of higher case endotoxin levels (odds ratio, 2.41; confidence interval 1.19 to 4.86). CONCLUSIONS Water contact behavior while wearing lenses is prevalent among soft lens wearers and is associated with higher case contamination. Practitioners may improve contact lens education to reduce water exposure and case contamination to reduce the risk of lens-related adverse events.