Contact Lens Care Goes Back to Basics

The FDA’s next step was a public workshop Microbiological Testing for Contact Lens Care Products held over two days (22-23) in January 2009.

The closing statements from the various representatives of the organizations that attended this workshop showed a high level of agreement with the recommendations and goals that resulted, i.e. a consensus was reached.

These can be summarized as follows:

  • It was noted that, although the single LCP most commonly associated (>50% of cases reported) with the acanthamoeba keratitis that precipitated the present crisis was withdrawn quickly and successfully, the steep decline in infection expected subsequently, did not occur. This suggested that other factors were involved and special attention has been given to the reduced disinfection of reticulated mains water supplies as one possible confounding factor. Concern was expressed about the difficulty of reversing any infestation of supply lines by offending organisms because of their known ability to encyst and/or form biofilms as an effective protective strategy
  • Current products were formulated using older, and now possibly unsound, criteria of likely microbial challenges. What was adequate ‘then’ has been shown to be wanting in the ‘new’ circumstances that confront us
  • Enhance the standards of microbial efficacy of lens care regimens without impacting adversely their ocular toxicity
  • While it will be a challenge, an appropriate set of test methods must be created to test a contact lens disinfection system’s/lens care system’s ability to deal with Acanthamoeba spp. in both trophozoite and encysted forms. Acanthamoeba castellanii (ATCC 50370) was nominated as the initial test organism species until subsequent scientific data suggests either an alternative or an additional species that should be added to the test panel of challenge organisms
  • Micro-organisms used as challengers to LCPs should consist of library strains (off-the-shelf) as well as recent clinical isolates (the ‘street-wise’ strains of the same organisms recovered from patients exhibiting active infections). The former represent a ‘best case’ scenario for LCP efficacy whereas the latter is usually a ‘worst case’ scenario and more of a challenge
  • Where feasible, the test methods should represent ‘real world’ scenarios that take known issues of no-compliance into account. Such issues should include: ‘topping up’ (topping off) lens case solution levels rather than complete replacement each time, reuse of solutions, evaporation, presence of ‘organic soil’ (finger-borne and other sources), use of smaller solution volumes than recommended, etc.
  • The creation of a surveillance system that would facilitate the detection of untoward movements in the incidence rates of ocular diseases and the uncovering of their aetiologies in a timely manner subsequently
  • Labeling of LCPs that encourage lens wearers to ‘rub & rinse’ their lenses. It was conceded that some allowance should be made for products that might meet the new (as yet undeveloped) antimicrobial guidelines without rubbing. It was felt that such an allowance would benefit such products because they addressed a known area of non-compliance among wearers
  • Labeling should address the issue of the role, if any, tap water may have in contact lens care (prohibition is the most likely recommendation esp. in view of some of the published study findings)
  • Existing LCPs should undergo recertification against the new standards once the latter has been established. This may require reformulation and/or deletion of some current products
  • It was hoped that draft guidelines would be circulated by mid-2009 and final standards before the end of 2009

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