Risk Factors for microbial bioburden during daily wear of silicone hydrogel contact lenses

Abstract

 

Purpose

 

Substantial microbial bioburden on contact lenses during extended wear and lid margins during daily wear have shown to be risk factors for the development of contact lens associated corneal inflammatory events (CIEs). This study assessed risk factors associated with substantial microbial bioburden of lids, cases, and silicone hydrogel contact lenses when worn daily wear

 

Methods

 

218 patients were enrolled in the Daily Wear Corneal Infiltrative Event study, fit to lotrafilcon A contact lenses, randomized to use either a preserved multipurpose solution (MPS) or a peroxide care system, and followed for 1 year. Lenses, lids, cases and transport saline were cultured at selected visits and considered to have substantial microbial bioburden when they harbored high levels of commensal or pathogenic organisms based on established criteria. Univariate and multivariate logistic regression analyses were conducted at the person level to examine which demographic and solution covariates were associated with significant bioburden at each location

 

Results

 

Univariate analyses revealed current or past smokers (vs. never-smokers), clerical occupations, and solution type were associated with a greater risk of microbial bioburden on lenses, cases, or both. Neither gender, age, nor healthcare occupations were associated with significant bioburden in any of the locations examined; additionally, neither solution type nor other demographic factors were associated with lid bioburden or saline contamination. In multivariate analyses, clerical (vs. non-clerical) occupations had significantly greater risk of microbial contamination on lenses (OR = 2.7 (95% Confidence Interval (CI) 1.04-6.8)) and cases (OR = 3.4 (95% CI 1.14-10.0)). Solution type was associated with microbial bioburden in cases (adjusted OR for the peroxide system = 7.5 (95% CI 3.8-15.1)) but not on lenses, lids or transport saline

 

Conclusions

 

Clerical occupations were associated with increased microbial bioburden of contact lenses and cases during daily wear use of silicone hydrogel lenses. Although a hydrogen peroxide care solution (compared to a MPS) was associated with increased lens case bioburden, this association was not found with bioburden on lids, lenses, or in transport saline and case contamination was not a risk factor for CIEs in this study

 

Keywords: 477 contact lens