A recent U.S. outbreak of corneal infections associated with a contact lens solution may have been related to external contamination, researchers said in the Journal of the American Medical Association (JAMA) Wednesday.
The Bausch & Lomb solution Renu with MoistureLoc was recalled from the worldwide market in May after the Centers for Disease Control and Prevention received multiple reports of a corneal infection called Fusarium keratits.
Fusarium is a fungus usually found in soil and plants. Microbial keratitis is a serious and rare infection that may lead to permanent vision loss or require corneal transplantation treatment.
According to JAMA, the annual incidence of microbial keratitis is four to 21 per 10,000 soft contact lens wearers.
Dr. Douglas C. Chang of the Centers for Disease Control and Prevention began a study on June 1, 2005, reviewing the outbreak's association with contact lens hygiene practices, products and activities. By June 30, 2006, researchers had identified 164 confirmed cases of Fusarium keratitis in the U.S.
"Our findings suggest that exposure to Fusarium was likely the result of extrinsic contamination of contact lens solution bottles or lens cases occurring outside of the manufacturing or storage processes, perhaps in patients' homes," the researchers wrote in their study published in the Aug. 23/30 issue of JAMA.
Fusarium was not found in the factory that produced the solution, the warehouse or any unopened solution bottles, the researchers said.
The researchers advised soft contact lens users to pay close attention to their hygiene practices, especially washing and drying hands before handling lenses and putting new lens solution into the storage case after each use.
Contact lens wearers should also pay close attention to product directions for contact lenses and lens solutions, they said.