ATLANTA (AP) - Advanced Medical Optics Inc. said Tuesday that the voluntary recall of a contact lens solution is not due to a manufacturing problem and is instead related to improper handling of lenses, resulting in eye infections that forced the product to be pulled from the shelves.
Government officials Friday warned people to throw away AMO Complete Moisture Plus Multi-Purpose Solution, using for cleaning and storing soft contact lenses, after an investigation linked it to a rare eye infection.
The solution seems to be a factor in cases of Acanthamoeba keratitis, a painful eye infection caused by a waterborne organism that, untreated, can lead to permanent vision loss or blindness, the Centers for Disease Control and Prevention said.
''It's not a manufacturing problem or a contamination issue,'' said James Mazzo, president and chief executive officer of Santa Ana, Calif.-based Advanced Medical Optics Inc., who added that the infection, also called ''AK,'' affects people who improperly handle contact lenses, such as disinfecting them with water or wearing them while swimming or showering.
''AK is something the vast majority of contact lens users typically avoid by following their eye practitioner's advice,'' Mazzo said. ''All of our products ... have always met and continue to meet FDA requirements. Moisture Plus does what it is required to do.''
CDC officials said they drew a link between the Advanced Medical Optics product and the infection because 58 percent of confirmed cases who wore soft contact lenses had used the solution in the month before onset of symptoms, and 39 percent had used only that solution.
They calculated that wearers of soft contact lenses who had the infection were at least seven times more likely to have used AMO Complete Moisture Plus than healthy people who wear soft contact lenses.
It's generally difficult to draw a strong statistical conclusion from a small number of cases, but in this case an association between the product and the infection was clear-cut, CDC officials said.
Health officials will continue to investigate why the association exists. But in the interest of public health, they decided a warning was necessary, said Dr. Sharon Roy, the CDC epidemiologist who led the investigation.
The CDC and the U.S. Food and Drug Administration are investigating 138 confirmed cases since January 2005.
CDC officials said people should discard the solution, throw out their current contact lenses and toss away the lens storage case. All of them may harbor the infecting amoeba, said Michael Beach, team leader in the CDC's division of parasitic diseases.
An estimated 85 percent of U.S. cases of Acanthamoeba keratitis occur in contact lens users, but it's extremely rare. The estimated prevalence is one to two cases per 1 million contact lens wearers. Contact lens wearers who practice proper lens care and people who don't wear contact lenses can still develop the infection.