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Recently, the Ophthalmic Devices Panel of the Medical Devices Advisory Committee to the Food and Drug Administration (FDA) met to discuss recommendations for guidance documents for contact lenses and care solutions.
Recently, the Ophthalmic Devices Panel of the Medical Devices Advisory Committee to the Food and Drug Administration (FDA) met to discuss recommendations for guidance documents for contact lenses and care solutions. The last guidance update took place in 1994 for contact lenses and in 1997 for care solutions. Since that time, outbreaks of Fusarium and Acanthamoeba have prompted increased scrutiny.
The FDA presented information on based on their assessment of the current trends and research carried out in FDA Laboratories:
• Demographics and patient noncompliance of contact lens users. Key problems such as “topping off” were highlighted with label and education approaches to increase compliance.
• Interactions of contact lens materials with multipurpose care product solutions
• Grouping system for silicone hydrogel (sihy) contact lenses and a potential screening method to assess preservative uptake and lens solution incompatibilities of contact lenses
• Variables that may impact care product disinfection efficacy from a microbiological perspective
• Impact of using tap water as a rinsing agent in the care of gas permeable (GP) lenses
“One of the key things the FDA raised was the option from moving away from microbiology to looking at uptake of preservatives to see if lens care solutions were compatible,” says Ralph P. Stone, PhD, former vice president of consumer products research and development at Alcon, who was present at the meeting.
Traditionally, contact lens materials were grouped into four categories based on charge (ionic, non-ionic) and water content (<50 percent water, >50 percent water). With the advent of more sihy materials to the market, clinicians and scientists found that they didn’t fit well into the four existing contact lens material groups. In addition, incompatibilities between certain lens care products and sihy materials were discovered. In 2007, Group 5 for sihy materials was added. Questions remained whether one group was sufficient to encompass the performance of all sihy materials.
New information about sihy material performance prompted the FDA to consider a new grouping strategy for these materials. Water content and ionic charge predict preservative update and release of some care solution components, surface treatment of sihy materials may limit diffusion of larger materials into the bulk material and may favor adsorption of some components over others, some types of silicone have a higher affinity for some solution components, and some materials my swell more than others (causing problems with standards tolerances). A comment indicated that the silicone in these materials are yet to be fully understood.
In developing contact lens care solutions, manufacturers must balance the ability to kill microorganisms (efficacy) with the potential toxicity to the human eye. The more toxic the product, the less comfortable for the user. More effective disinfectant can lead to less safe products if not balanced. According to Dr. Stone, the discussion failed to address this concept.
Says Dr. Stone: “It appeared to be the recommendation from the panel that any changes guidance ought to be done as a joint collaboration among all parties involved in this process, not just the FDA but ISO and ANSI, as well academia the industry, and the professionals in the field. Industry and Academia has more people who can and do do this testing than anyone else in the world. It is essential that any new testing protocols included in the guidance for these products be challenged in laboratories throughout the US and around the world.”
Other discussion centered on the use of tap water with GP lenses due to its association with Acanthamoeba keratitis. Some panelists were opposed to tap water use, some advised it be used only before disinfection, and still others didn’t consider tap water use a concern given the lack of evidence citing tap water a cause of Acanthamoeba keratitis.
“It was a good start,” says Dr. Stone. “The need for us to work together, the need for the FDA to work with other standard-setting organizations and other experts around the world is critical.”