Impact of Lens Case Hygiene Guidelines on Contact Lens Case Contamination

ArticleinOptometry and vision science: official publication of the American Academy of Optometry 88(10):E1180-7 · July 2011with80 Reads
DOI: 10.1097/OPX.0b013e3182282f28 · Source: PubMed
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.
    • "Microbial contamination in contact lens cases was found in 50% of the total cases in our study. It falls within the range reported in previous studies [13,14] but this is quite low than those reported by Dantam et al. [15] (82%) and Wu et al. [16] (82%). This comparatively lower rate of contamination might be because the agar plates were incubated in normal atmosphere in the present study, while Dantam and Wu used carbon dioxide enriched atmosphere. "
    [Show abstract] [Hide abstract] ABSTRACT: To determine the rates of microbial contamination and identify contaminants associated with contact lens (CL) care accessories. To investigate self-reported compliance levels with care of CL accessories and its association with contamination level. A total of 46 CL cases and care solutions from asymptomatic soft contact lens wearers were collected. Samples from the CL cases and care solutions were cultured for microbiological identification and enumeration. A questionnaire regarding compliance to care and hygiene procedures were administered to each subject on their visit. The percentage of microbial contamination for CL cases and care solutions was 50% and 10.9%, respectively. All the contaminants were bacterial. Staphylococcus aureus (37.0%, 17 of 46 cases) and Escherichia coli (8.7%, 4 of 46 cases) were the most common microorganisms detected in CL cases. In care solutions, S. aureus (8.7%, 4 of 46 samples), Pseudomonas aeruginosa (2.2%, 1 of 46 samples) were common contaminants. CL cases and care solutions that were used for <3 months were significantly less contaminated than those used for >3 months (10.9% versus 39.1%, p<0.05). Polyquad and Aldox based MPS solution showed no contamination. Subjects with medium or low compliance had highly significant rates of contaminations both in CL cases and solutions than for subjects with high compliance (p<0.05). Nepalese Soft CL wearers are at high risk of developing ocular complications due to high CL case and solution contamination. Frequent replacement of CL cases and solutions, as well as good compliance is recommended to reduce risk of contamination.
    Full-text · Article · Jul 2013
    • "Bacterial biofilms are more easily removed from non-ridged lens cases than ridged cases in vitro [47]. Mechanical steps such as digital case cleaning and tissue-wiping cases dry appear to reduce frequency and degree of storage case contamination both in vitro and in vivo474849. Modifications, such as adding silver to lens cases, can halve the rate of gram-negative colonization (and fungi depending on manufacturer) and significantly reduce the number of organisms present both in vitro and in vivo. "
    [Show abstract] [Hide abstract] 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.
    Full-text · Article · Jan 2013
  • [Show abstract] [Hide abstract] ABSTRACT: Lens storage case hygiene practices are important for safe contact lens wear. However, the effectiveness of the manufacturer's direction for use and various cleaning regimens in reducing biofilm load is yet to be evaluated and compared. This in vitro study compared the effectiveness of several cleaning methods using silver-impregnated lens case and hydrogen peroxide disinfection systems. Biofilms of Pseudomonas aeruginosa 122 and Staphylococcus aureus ATCC 6538 were grown in silver-impregnated and hydrogen peroxide lens cases. After the establishment of the biofilms, the silver-impregnated case was subjected to one of four cleaning regimens: "manufacturer's directions for use--rinsed and recapped"; "rubbed, rinsed, and recapped"; "rubbed, rinsed, and air dried"; or "rubbed, rinsed, tissue wiped, and air dried." Hydrogen peroxide cases underwent one of two regimens: "manufacturer's directions for use--rinsed with saline and air dried" or "soaked in solution for 6 hrs." The level of residual bacteria was quantified. The efficacy of each cleaning regimen was then compared. Mechanical rubbing and wiping of silver-impregnated cases and soaking hydrogen peroxide cases in hydrogen peroxide were the most effective treatments for reducing biofilms. Once the silver-impregnated cases were rubbed, air drying or recapping the cases did not have any significant effect on the level of the biofilm. The level of initial biofilm formation of silver-impregnated cases was significantly lower than those of polypropylene lens cases (P<0.0001). Rubbing and rinsing with disinfecting solution and wiping with a tissue can be considered to be effective in removing biofilms from silver-impregnated lens cases. Resoaking the basket-type lens case in hydrogen peroxide between use was found to be effective in removing biofilms from these cases.
    Article · Nov 2011
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