Contact Lens Care & Compliance
Update From the GSLS: The Evolving Standards of Lens Care
BY SUSAN J. GROMACKI, OD, FAAO
I had the pleasure of moderating the Contact Lens Care and Compliance Panel at this year’s Global Specialty Lens Symposium (GSLS) in Las Vegas. It was a privilege to share the podium with some of our profession’s leaders in these topical areas. Following is a summary of the first presentation by Loretta Szczotka-Flynn, OD, PhD, FAAO.
FDA Guidance Update
Dr. Szczotka-Flynn discussed the United States Food and Drug Administration’s (FDA) role in lens care standards and its progress toward developing a new guidance document, last updated in 1997. She had been a member of the 2008 FDA Ophthalmic Devices Panel convened in response to the Fusarium and Acanthamoeba keratitis outbreaks.
She reported that, based on a series of 2012 publications in Eye & Contact Lens, the FDA has been working on a research plan to improve the clinical testing of lens care solutions. First, it has been studying the physiochemical properties of silicone hydrogel (SiHy) contact lenses to classify them into their own material categories with regard to solution testing and compatibility. In addition to the four current groupings for soft lenses, the FDA has proposed a group 5 for silicone hydrogel lenses, which would then be subdivided into five subgroups:
• Group 5-A: Low-water-content, non-ionic, and surface-treated lenses
• Group 5-B1: Low-water-content, non-ionic, non-surface-treated, and hydrophilic monomer-containing lenses
• Group 5-B2: Low-water-content, non-ionic, non-surface-treated, and semi-interpenetrating network-containing lenses
• Group 5-C: High-water-content, non-ionic lenses
• Group 5-D: Ionic materials, both low- and high-water-content lenses
Second, the agency has been studying antimicrobial efficacy of multipurpose solutions in the presence of a contact lens. The current Stand Alone testing methods do not include a lens or a case. It has found that soft contact lenses uptake multipurpose solution preservatives, with rates that differ depending on material and preservative. The more preservatives/biocides/disinfectants that are uptaken by a material, the lower the preservative concentration that remains in the solution. As a result, the disinfection efficacy is clearly reduced (Eydelman, 2012; Green, 2012).
Third, the FDA has been developing test methods for Acanthamoeba, an organism not currently utilized by the FDA in testing. The suggested protocols include recommended methods to grow and encyst amoebas.
Biofilms and Lens Disinfection
Dr. Szczotka-Flynn also presented her own and others’ research on biofilms. Biofilms are multicellular formations of organisms and substrates. They are more difficult to eradicate compared to single microorganisms, can impart resistance to lens care products, and can transfer from case to lens to eye, causing infection. Dr. Szczotka-Flynn cited research demonstrating that the ability to form biofilms is a key aspect to pathogenicity. She then discussed her own research, which showed that all of the soft lens care systems tested were efficacious against all of the planktonic (free floating) bacteria and fungi. However, when the bacteria or fungi were allowed to form biofilms, solution efficacy was greatly reduced in most care solutions. The only care solution that consistently maintained disinfection efficacy against fungal and bacterial biofilms formed on lenses was hydrogen peroxide. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #208.
Dr. Gromacki is a diplomate in the American Academy of Optometry’s Section on Cornea, Contact Lenses and Refractive Technologies and practices in Chevy Chase, Md.