The Environmental Protection Agency?s mandate to
reduce the amount of chemicals used to sanitize public
water, including pools, may be the cause behind a recent
increase in a rare eye infection among contact lens users,
At least 40 cases of acanthamoeba keratitis
were reported between June 1, 2003, and Nov. 30, 2005, in
the Greater Chicago area, according to a study at the
University of Illinois at Chicago?s Department of
Ophthalmology and Visual Sciences. In the past, only two or
three cases occurred each year.
In 1998, the EPA passed a rule lowering the amount of
hazardous chemical byproducts produced when organic matter
reacts with water disinfectants. Chicago, where the study
originated, was expected to become completely compliant by
As a result, researchers theorized, the lowered amount
of disinfectants allowed more acanthamoebas to
survive, entering the pool and becoming trapped behind
swimmers? contact lenses.
?Clinicians need to be aware that if our
hypothesis is correct and the Chicago outbreak is related
to recent changes in U.S. EPA regulations, the potential
exists for a similar dramatic increase in AK cases
nationally,? wrote the authors of the study.
AK is a severe and painful eye infection of the cornea
caused by the amoeba Acanthamoeba. It can cause
scarring and even blindness. The disease requires intensive
therapy and often a surgical transplant of the cornea.
According to the study, 85 percent of cases occur in
contact wearers, and those with poor lens hygiene or who
swim with contacts increase their risks.