Impact of lens case hygiene guidelines on contact lens case contamination.
ABSTRACT Lens case contamination is a risk factor for microbial keratitis. The effectiveness of manufacturers' lens case cleaning guidelines in limiting microbial contamination has not been evaluated in vivo. This study compared the effectiveness of manufacturers' guidelines and an alternative cleaning regimen.
A randomized cross-over clinical trial with two phases (n = 40) was performed. Participants used the lens types of their choice in conjunction with the provided multipurpose solution (containing polyhexamethylene biguanide) for daily wear. In the manufacturers' guideline phase, cases were rinsed with multipurpose solution and air dried. In the alternative regimen phase, cases were rubbed, rinsed with solution, tissue wiped, and air-dried face down. The duration of each phase was 1 month. Lens cases were collected at the end of each phase for microbiological investigation. The levels of microbial contamination were compared, and compliance to both regimens was assessed.
The case contamination rate was 82% (32/39) in the manufacturers' guideline group, compared with 72% (28/39) in the alternative regimen group. There were significantly fewer (p = 0.004) colony forming units (CFU) of bacteria from cases used by following the alternative regimen (CFU range of 0 to 10, and median of 12 CFU per well) compared with that of the manufacturer's guidelines (CFU range of 0 to 10, and median of 28 CFU per well). The compliance level between both guidelines was not significantly different (p > 0.05).
The alternative guidelines are more effective in eliminating microbial contamination from lens cases than that of the current manufacturer's guideline. Simply incorporating rubbing and tissue-wiping steps in daily case hygiene reduces viable organism contamination.
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ABSTRACT: Eye care practitioners (ECPs) would tend to agree that wearing contact lenses increases the risk for infection, but millions of patients are still fitted with lenses every year because ECPs feel that the risk is manageable and that their patients' eye health can be protected. The Fusarium and Acanthamoeba keratitis outbreaks of years past were a wake-up call to manufacturers, ECPs, and regulatory agencies that risk cannot be managed without diligence, and that the complex relationship between contact lens materials, contact lens solutions, and compliance needs to be better understood in order to optimize the efficacy of contact lens care and improve care guidelines.Contact Lens and Anterior Eye 01/2013; 36:S14–S21. · 2.00 Impact Factor
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ABSTRACT: This study aims to investigate the association of compliance amongst lens wearers and lens case contamination as assessed by the microbial profile of lens cases. Fifty-two asymptomatic lens wearers filled out questionnaires seeking demographic data and several aspects of compliance to lens wear. Subsequently, contamination profiles of the inside bottom and rim of their lens cases was obtained for bacteria, fungi and Acanthamoeba. The association of the self-reported responses in the questionnaire with contamination profile of the lens case was then analyzed. Based on compliance criteria, 21% of the participants were described as fully compliant lens wearers. Contamination of lens case was prevalent in 42% of the cases. Frequent non-compliant behaviours reported by study participants included, showering and sleeping with contact lenses, and irregular lens case replacement. In comparison to soft contact lens wearers prevalence of non-compliance and contamination amongst rigid gas permeable (RGP) lens wearers was significantly greater. There was a statistically significant correlation between bacterial contamination and current case age. These results suggest that majority of lens wearers do not fully comply with recommendations for lens wear and case care. Crucially, none of the fully compliant patients had contaminated lens cases. However it would appear that several non-compliant behaviours significantly increase the risks of case contamination. These results suggest that greater efforts should be invested with lens wearers to ensure enhanced compliance as this is likely to reduce the possibility of case contamination.Contact lens & anterior eye: the journal of the British Contact Lens Association 09/2013;
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ABSTRACT: To describe the adhesion properties of Acanthamoeba castellanii trophozoites to silicone hydrogel contact lenses of first generation (lotrafilcon A), second generation (galyfilcon A), and third generation (comfilcon A) and correlate the results with their specific surface characteristics, time of interaction, and suspension media. Qualitative and quantitative assessments of the adhesion of 200 trophozoites of A. castellanii on contact lenses in culture medium (Bacto Casitone) and isotonic saline (IS) at different time points (15 minutes and 6 hours) were determined. By scanning electron microscopy, A. castellanii trophozoites were observed firmly adhered to the surface of hydrogel lenses after 15 minutes of interaction. The surface of lotrafilcon A lenses on which amoebae adhere better (16.4±10.2 amoebae/lens section) is rough and folded, which increases the contact surface with trophozoites, allowing acanthopodia to attach firmly. Contrarily, galyfilcon A lenses have a smoother surface, and lower numbers of amoebae were observed adhered to these lenses (4.7±2.9 amoebae/lens section). Even fewer amoebae adhered to the smoother surface of the comfilcon A lens (2.2±1.7 amoebae/lens section). Trophozoites showed similar behavior in both Bacto Casitone medium and IS. A rough surface may contribute to better adhesion of amoebae to silicone hydrogel lenses. Although a reduced numbers of trophozoites adhered to smooth lenses, trophozoites are a risk factor for amoebic keratitis. Isotonic saline facilitated trophozoite survival, suggesting that homemade saline solutions may contribute to the persistence of trophozoites, especially when there is no proper hygiene regimen used with the contact lens cases.Eye & contact lens 04/2014; · 1.68 Impact Factor