Evaluation of Contact Lenses by Microbial Enumeration and Protein Determination

Jt, Barr; Wj, Lapple; Ac, Snyder; Jc, Hsu; Tuovinen, Olli H.

doi:10.1097/00006324-198806000-00007

Cited by 8 publications

(3 citation statements)

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“…12–18 To date, microorganisms that colonize lid margins13, 17, hands14, 16, lens cases12, 18, and the domestic water supply17 have been implicated as such sources. Furthermore, other studies have looked for associations between lens contamination and physical lens properties or patient factors 19–24. Only length of time since a lens was first used20, occasional wear23, avoidance of rinsing lenses prior to insertion23, and protein deposition19, 24 have been implicated, although in later studies no association was found between lens deposits and lens bacterial bioburden 20, 22…”

mentioning

confidence: 99%

Risk Factors for Contact Lens Bacterial Contamination During Continuous Wear

Szczotka-Flynn

Bajaksouzian²,

Jacobs³

et al. 2009

Optometry and Vision Science

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Purpose Microbial contamination of contact lenses is associated with corneal infection and inflammation. This study determined which microbiological, clinical and demographic factors are associated with bacterial contamination of a silicone hydrogel contact lens when worn for continuous wear. Methods Two hundred five normal subjects were enrolled in the Longitudinal Analysis of Silicone Hydrogel (LASH) Contact Lens Study and were fitted with lotrafilcon A lenses for monthly continuous wear and followed for 1 year. Lenses were aseptically removed after 1 week and 4 months of wear and cultured using an agar sandwich technique. Lids and conjunctiva were routinely cultured at baseline, and after 1 week and 4 months of continuous wear. Lenses and ocular sites were considered to have substantial microbial bioburden when they harbored pathogenic organisms or high levels of commensal organisms. Univariate and multivariate logistic regression analyses were conducted to examine whether substantial conjunctival or lid bioburden, subject demographics, lens wearing history, symptoms, and biomicroscopic signs were associated with lens bioburden. Results About one-third (32.4%) of subjects had substantial bacterial bioburden in either eye across multiple visits. Over half (53.2%) and about one-tenth (11.7%) of subjects had substantial lid and conjunctival bioburden, respectively, and 11.2% discontinued due to discomfort. The adjusted odds ratios (and 95% confidence intervals) for presence of substantial lens bioburden were 2.49 (1.17–5.30), 4.24 (1.45–12.40), and 4.11 (1.17–14.46) for substantial lid bioburden, substantial conjunctival bioburden, and lens discomfort, respectively. Conclusions Bacterial contamination of silicone hydrogel contact lenses is common during continuous wear. Substantial lens bioburden is associated with discomfort precluding successful continuous wear. The presence of substantial lid and conjunctival bioburden are associated with a 2.5 fold and over 4 fold greater risk of substantial lens bioburden and are likely the major routes of contamination.

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mentioning

confidence: 99%

Risk Factors for Contact Lens Bacterial Contamination During Continuous Wear

Szczotka-Flynn

Bajaksouzian²,

Jacobs³

et al. 2009

Optometry and Vision Science

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“…In 1993 Hart et al 35 correlated lens age with the number of CFU cultured per lens in a cross-sectional study of patients wearing nondisposable soft lenses aged between 0.5 and 12 months and found a statistically significant correlation in an EW group of patients ( P = 0.028). In 1988, Barr et al 50 did not find a correlation between CFU counts per lens and lens age based on a cross-sectional survey of nondisposable lenses worn between 1 and 48 months. In both the studies, the patients used various lens types, disinfection regimens, and wearing schedules.…”

Section: Bioburdenmentioning

confidence: 97%

“…Thus, the combination of protein deposition supporting microbial growth and potentially compromising the ocular surface would be especially worrisome. In 1988, Barr et al 50 have shown a positive linear association between in vivo protein deposition and bacterial CFU counts on low Dk nondisposable soft lenses. However, in vitro studies are conflicting in this regard.…”

Section: Bioburdenmentioning

confidence: 99%

Microbial Contamination of Contact Lenses, Lens Care Solutions, and Their Accessories: A Literature Review

Szczotka-Flynn

Pearlman

Ghannoum

2010

Eye &Amp; Contact Lens: Science &Amp; Clinical Practice

210

155

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Purpose A contact lens (CL) can act as a vector for microorganisms to adhere to and transfer to the ocular surface. Commensal microorganisms that uneventfully cohabitate on lid margins and conjunctivae and potential pathogens that are found transiently on the ocular surface can inoculate CLs in vivo. In the presence of reduced tissue resistance, these resident microorganisms or transient pathogens can invade and colonize the cornea or conjunctiva to produce inflammation or infection. Methods The literature was reviewed and used to summarize the findings over the last 30 years on the identification, enumeration, and classification of microorganisms adherent to CLs and their accessories during the course of normal wear and to hypothesize the role that these microorganisms play in CL infection and inflammation. Results Lens handling greatly increases the incidence of lens contamination, and the ocular surface has a tremendous ability to destroy organisms. However, even when removed aseptically from the eye, more than half of lenses are found to harbor microorganisms, almost exclusively bacteria. Coagulase-negative Staphylococci are most commonly cultured from worn lenses; however, approximately 10% of lenses harbor Gram-negative and highly pathogenic species, even in asymptomatic subjects. In storage cases, the incidence of positive microbial bioburden is also typically greater than 50%. All types of care solutions can become contaminated, including up to 30% of preserved products. Conclusions The process of CL-related microbial keratitis and inflammation is thought to be preceded by the presence or transfer or both of microorganisms from the lens to the ocular surface. Thus, this detailed understanding of lens-related bioburden is important in the understanding of factors associated with infectious and inflammatory complications. Promising mechanisms to prevent bacterial colonization on lenses and lens cases are forthcoming, which may decrease the incidence of microbially driven CL complications.

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Comparative case contamination: Three disinfection systems

McKenney¹,

Ajello²

1991

International Contact Lens Clinic

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Evaluation of Contact Lenses by Microbial Enumeration and Protein Determination

Cited by 8 publications

References 0 publications

Risk Factors for Contact Lens Bacterial Contamination During Continuous Wear

Risk Factors for Contact Lens Bacterial Contamination During Continuous Wear

Microbial Contamination of Contact Lenses, Lens Care Solutions, and Their Accessories: A Literature Review

Comparative case contamination: Three disinfection systems

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