In the past several years, contact lens solutions, including ReNu with MoistureLoc and Advanced Medical Optics Complete MoisturePlus, have been linked to potentially blinding eye infections. Now, a group of Food & Drug Administration (FDA) advisors has recommended that contact lens solutions be subjected to more stringent testing to insure their safety. The panel also recommended that stronger safety warnings be added to the labels of multi-purpose contact lens solutions so that users can know how to avoid contaminating the products.
Contact lens solutions have been subjected to several recalls because of contamination problems that resulted in some users developing serious eye infections. In 2006, Bausch & Lomb issued a worldwide recall of ReNu with MoistureLoc Contact Lens Solution after it was linked to hundreds of cases of Fusarium Keratitis, a rare eye infection that has the potential to cause blindness. Following an investigation, the Centers for Disease Control determined that bad hygiene habits among users were not to blame for the infections, but that the contact lens solution appeared to have poor disinfectant qualities.
Last year, at least 21 cases of infections involving the water-borne Acanthamoeba parasite were linked to Advanced Medical Optics (AMO) Complete MoisturePlus solution, prompting the Santa Ana, California-based company to recall the product. That AMO recall followed another issued in November 2006, when 2.9 million packets of AMO Complete MoisturePlus Multi-Purpose contact-lens solution and Active Packs were recalled after lots sold in Japan were found to have bacterial contamination. The recall included 183,000 Complete MoisturePlus units sold in the United States. AMO traced the contaminated units to a plant in China and found that Ralstonia bacteria had compromised the disinfectant in the solution and were eating away at the oxygen in the bottles.
Since the outbreaks and recalls, critics of contact lens solution makers have contended that current testing methods are not enough to insure the products’ safety. That argument gained added weight earlier this year when researchers at the Center for Medical Mycology found ReNu with MoistureLoc was unable to resist contamination because the strain of Fusarium responsible for the 2006 outbreak had the ability to form biofilms. Biofilms are clusters of microbes held together by a glue-like matrix. This structure made the Fusarium extremely resistant to contact lens solutions and the body’s own immune system. Unfortunately, contact lens solutions are not required to be tested against microbes with the ability to form biofilms. In fact, RenNu with MoistureLoc and other contact lens solutions are tested against a rare type of fungus obtained from a patient in Nigeria in 1970s, which critics say has no real-world applicability.
In the case of the recalled AMO contact lens solution, there is no requirement at this time for solutions to be tested against Acanthamoeba. Following the 2007 recall, researchers found that AMO Complete MoisturePlus had no ability to kill the parasite.
The FDA panel strongly recommended that the agency revamp its requirements for the way companies test their contact lens solutions for safety before selling them. The panel also recommended a variety of strong new consumer warnings for the solutions, including cautions that reusing lens solution can lead to blindness.
The FDA is not bound to follow recommendations of advisory panels, but in most cases, it does so.
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