editor’s perspective

Revisiting FDA Lens Material Classification

By Jason J. Nichols, OD, MPH, PHD, FAAO

For more than 20 years, the U.S. Food and Drug Administration (FDA) has used a classification system for contact lens materials that categorizes them based on two key components: water content and ionicity. Thus, there are four material classifications: Group 1 (low water, non-ionic), Group 2 (high water, non-ionic), Group 3 (low water, ionic), and Group 4 (high water, ionic). The original draft guidance was first presented in 1985, and the process was said to indeed have been a working collaboration between the FDA and the contact lens community, including industry.

Since that time, new materials have emerged in the market. As we are all very well aware, silicone hydrogel materials entered the U.S. market in the late 1990s. Fast forward to 2012—nearly 13 years later! We’ve learned a lot about silicone hydrogels over this time. We’ve seen industry produce what have been termed second-and third-generation materials. We’ve seen issues arise in caring for silicone hydrogels that might not have been predicted based on contemporary wisdom regarding the original HEMA-based chemistry of contact lens polymers or the original FDA classification system. We’ve seen issues, including recalls, with contact lens care solutions (which are also regulated as devices).

In my Editor’s Perspective from the April 2009 issue, I noted the outcry for reconsideration of the FDA material classification scheme. That was nearly 10 years after the introduction of silicone hydrogel materials and nearly three years ago today. The FDA recently presented a draft of new guidance at a meeting with limited attendance; to our knowledge, the FDA has not made the draft otherwise public for comment to date. While we’ve heard of a possible addition of a new group (Group 5) for silicone hydrogels, the FDA has been slow to provide many details on this.

I realize that drafting regulation takes time—but it is unfortunate to not have a more open and efficient process on contact lens material classification and care solution guidelines. Innovation in device development is difficult in and of itself—we can only imagine how issues with the regulatory environment would make things even more difficult for manufacturers.