contact lens care and compliance

Reporting on the FDA Microbiology Workshop

BY SUSAN J. GROMACKI, OD, MS, FAAO

In the wake of the Fusarium and Acanthamoeba keratitis outbreaks among contact lens wearers, the United States Food and Drug Administration (FDA) responded by initiating plans to revise its premarket testing and labeling recommendations for soft contact lens care products. On June 10, 2008, the FDA then sought the recommendations of the Ophthalmic Devices Advisory Panel of experts as well as the public. (This is summarized in my Contact Lens Care columns from October and December 2008 and in my Contact Lens Care and Compliance column from February 2009.)

This panel unanimously recommended that the FDA add Acanthamoeba to its test organisms for lens care products. However, developing a standardized test method and performance criteria are complex tasks, in that the various laboratory and clinical isolates of Acanthamoeba strains have varying resistance to disinfecting agents; the organism can morph from a trophozoite form to a more resistant cyst form; and care must be taken that solutions do not cause ocular toxicity.

Evaluating Soft Lens Disinfection Testing

The FDA convened a workshop titled, "Microbiological Testing for Contact Lens Care Products," on Jan. 22-23, 2009. This event was co-sponsored with two optometry and two ophthalmology professional associations. The purpose of the workshop was for the FDA to collaborate with outside experts to facilitate the development of standardized methodologies and performance criteria for evaluating the elimination or kill of Acanthamoeba in contact lens care products.

To this end, the workshop included breakout discussions by scientific experts to discuss the critical test parameters that the co-sponsors identified for evaluating the activity of contact lens care products against Acanthamoeba. The workshop participants — experts from optometry, ophthalmology, science, academia, and industry — agreed on many key testing parameters. There was majority agreement that both trophozoite and cystic forms of the parasite be included in testing and that an American Type Culture Collection (ATCC 50370) laboratory strain Acanthamoeba castellananii be used in the testing.

The participants also agreed that "encystment" rates in the presence of disinfecting agents should be evaluated and that it is premature to set an acceptable performance threshold for disinfection efficacy before developing a specific test method. The FDA will continue to collaborate with outside experts and standards development organizations to develop and validate a standardized test method.

In light of noncompliance's role in the outbreaks, a portion of the second day of the meeting involved presentations with question-and-answer sessions regarding "real world" disinfection efficacy testing for all microorganisms. Consensus was reached that this needs to be incorporated into the FDA's next set of testing standards. Several meeting participants indicated that this topic is well-worth revisiting, perhaps with a workshop of its own.

A Great First Step

A special thank you needs to be extended to the FDA and to all workshop participants. Their collegiality was vital in providing the FDA a necessary first step toward establishing final standards for the disinfection of Acanthamoeba. Although there is still work to be done, practitioners and patients alike should appreciate the commitment of all involved to ensure that keratitis outbreaks among contact lens wearers do not happen again. CLS

Dr. Gromacki is a Diplomate in the Cornea and Contact Lens section of the American Academy of Optometry. She lives in West Point, New York.