Acanthamoeba Keratitis

A rare infection of the eye called Acanthamoeba keratitis hit the news this weekend with an outbreak of at least 138 cases confirmed in 35 states and Puerto Rico. The infection is caused by a microscopic parasite of the genus Acanthamoeba which is the most common free-living amoebae in fresh water and soil.


The amoebae attack the cornea, potentially leading to a necessary transplant or blindness. Contact lens wearers appear to be most at risk of becoming infected and a link to a lens cleaning solution has been identified with a resulting voluntary recall.

Epidemiologists from the Centers for Disease Control and Prevention have linked the acanthamoeba keratitis outbreak to AMO Complete Moisture Plus Multi-Purpose Solution. Advanced Medical Optics of Santa Ana, Calif., manufactures the solution, which is used to clean and store soft contact lenses.

AMO said there was no evidence to suggest that its product was contaminated with acanthamoeba and that it took its action as a precaution.

Federal officials have advised consumers to stop using the solution immediately and to discard all partly used or unopened bottles and switch to alternative products.

They have also advised people to throw out their current contact lenses and the lens storage cases because they may harbor the acanthamoeba parasite.

And, officials said, those who have used the product should call an eye doctor if they have experienced eye pain or redness, blurred vision, sensitivity to light, the feeling of something in the eye or excessive tearing. [my bold]

The Food and Drug Administration (FDA) has issued a bulletin. The Centers for Disease Control (CDC) has issued a health advisory. Also see the latest dispatch of the Morbidity and Mortality Weekly Report (MMWR).

Lastly, be aware that people who have compromised immune systems are at greater risk of infection by the parasite.