Evaporation of Contact Lens Solution Reduces Effectiveness

Partially evaporated contact lens solution loses much of its disinfectant ability, according to a new study. Many contact lens wearers unwittingly use partially evaporated solution, which can occur when contact lens wearers reuse solution or fail to recap their lens storage case.

Of all the contact lens solutions tested, Bausch + Lomb’s <"http://www.yourlawyer.com/topics/overview/renu_contact_solution">ReNu with MoistureLoc lost the most disinfectant ability when it was partially evaporated. ReNu with MoistureLoc was subject to a worldwide recall in 2006 when it was linked to an outbreak of Fusarium keratitis, a potentially blinding eye infection. According to the authors of the study, the loss of disinfectant ability that accompanies partial evaporation may have been a significant factor in that outbreak.

This new study, published in Contact Lens & Anterior Eye, was conducted by researches at Abbott Laboratories, a maker of contact lens solutions. The scientists used a steam of air to evaporate various contact lens solutions to 2-to-4 times their normal concentration. They then compared the ability of partially evaporated solution to kill fungal (Fusarium solani and Candida albicans) and Acanthamoeba microorganisms to non-evaporated solutions.

Of the solutions tested, ReNu with MoistureLoc lost 75 to 99 percent of its ability to kill Fusarium fungi, 90 to 100 percent of its effectiveness against Candida fungi, and 29 to 33 percent of its effectiveness against Acanthamoeba microorganisms. Other solutions that lost disinfectant ability included Alcon’s Opti-Free Replenish (lost 72 to 90 percent against Fusarium and Candida fungi, and 10 to 61 percent against Acanthamoeba); Bausch + Lomb’s ReNu MultiPlus (lost 72 to 90 percent against Fusarium and Candida fungi, and 10 to 61 percent against Acanthamoeba); Ciba Vision’s AQuify Multi-Purpose (lost 34.5 percent of its effectiveness against Candida); and Bausch + Lomb’s Biotrue (lost 48 percent against Candida fungi).

Bausch + Lomb pulled ReNu with MoistureLoc from Asian markets in February 2006, and did the same in the US in April of that year, after it was linked to the outbreak of Fusarium keratitis. The company would ultimately issue a worldwide recall of ReNu with MoistureLoc on May 15, 2006.

A US Centers for Disease Control (CDC) report on the outbreak found that those infected with Fusarium keratitis were 20 time more likely to have used the ReNu with MoistureLoc solution. The CDC report 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. The CDC ultimately confirmed 180 cases of Fusarium keratitis in the US. According to the Associated Press, at least 60 more Americans needed vision-saving corneal transplants.

The ReNu with MoistureLoc debacle spawned nearly 2,000 personal injury lawsuits.

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