contact lens care
FDA Begins to Take Action Regarding Lens Care — Part 2
BY SUSAN J. GROMACKI, OD, MS, FAAO
In my last column I reviewed the first topics discussed at the United States Food and Drug Administration's June Ophthalmic Devices Panel meeting. The six points reviewed modifications to pre-clinical and clinical testing for contact lens care products and to product labeling. Here are two more questions posed by FDA official James Saviola, OD, followed by the panel's recommendations.
Clinical Issues, Staining
Dr. Saviola: "Number 3 has three parts. The first part is regarding clinical issues. Please discuss your recommendations for an additional follow-up visit at two hours in order to assess for solution-related corneal staining. For the second part, please discuss whether this additional follow up should be included in lens care products and/or lens guidance. And the final, part three, please provide your recommendations on the inclusion of silicone hydrogel lenses in the clinical investigations of contact lens care products."
The panel recommended that the FDA should not require an additional two-hour follow-up visit in manufacturer clinical studies to perform fluorescein staining evaluation. Loretta Szczotka-Flynn, OD, MS, cited a paper from ARVO 2008 which demonstrated that polyhexamethylene biguanide (PHMB) binds to mucin; then fluorescein combined to that complex.
"What we might be seeing is basically the preservative somehow binding to this mucin, and that's what's staining and that's why it goes away so quickly," Dr. Szczotka-Flynn said. "So we don't really even know what that staining is … another reason to reinforce why we shouldn't try to make correlations between the staining and a product's performance."
The panel also recommended including silicone hydrogel lenses in clinical investigations of lens care products.
The fourth question Dr. Saviola asked: "Microbiology. Please discuss your proposal to revise the current Regimen Test in order to improve predictability of ‘real-world’ performance and include the following topics in your discussion: First point, testing marketed silicone hydrogel lenses; second point, defining worst-case rub and rinse times; for example, five-second rub and five-second rinse, total time. B: in microbiology, please discuss your recommendations for adding Acanthamoeba as a challenge organism in disinfection efficacy testing. C: please discuss our proposal for developing standardized test methods to evaluate the effects of preservative uptake by contact lenses on disinfection efficacy. Additionally, please comment on use of these tests to determine post-disinfection storage times in an unopened lens case. And finally, under micro, please discuss our proposal for modifying disinfection and preservative efficacy testing by two points, testing at the lower end of the active ingredient specifications to simulate worst-case conditions; and second point, including more resistant clinical isolates in these tests."
The panel agreed that the FDA Regimen Test for solution approval should include a more diverse and representative set of infectious organisms including Acanthamoeba, which is currently not a tested organism. Testing should be made more rigorous to include real-world scenarios such as solution evaporation.
In my next column, I will discuss the fifth and sixth points as well as the FDA's next step: a Contact Lens Microbiology Workshop scheduled for Jan. 22-23, 2009. 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.