DAVID GREENE, HOST:
OK. If you wear contact lenses, you're in a club with 40 million other Americans. Most people probably think they're taking care of the contact lenses properly. But a recent study finds that's not the case. In fact, as NPR's Patti Neighmond reports, research has found practically nobody is taking proper hygienic care of their contacts.
PATTI NEIGHMOND, BYLINE: Cleaning and storing contact lenses isn't complicated, but it does require adherence to certain simple but important steps. And it turns out most people are taking some risky shortcuts.
DANIELLE ROBERTSON: For the most part, patients know what they should be doing, but yet they fail to do it.
NEIGHMOND: Danielle Robertson is a vision scientist at the University of Texas, Southwestern Medical Center, who recently surveyed 433 people who wore contacts. It turned out less than one percent were doing everything right. That means 99 percent were doing something wrong. Most commonly, it had to do with storage. When contacts aren't being worn, they're supposed to be kept in a small plastic container full of sterile solution. Robertson says too many people didn't bother changing it; they just topped it off.
ROBERTSON: Topping off means at the end of the day you go, you take the lid off your case. You still have some solution left from the night before. So rather than dump it out, you just squirt a little extra in.
NEIGHMOND: Big mistake, she says, leftover solution in the lens case is often already contaminated with bacteria.
ROBERTSON: So if you get bacteria in that lens case and it's sitting in old solution that's no longer effective all day, in that wet environment, the bacteria will continue to grow and they'll form little communities called biofilms.
NEIGHMOND: Biofilm, a sort of bacterial slime.
ROBERTSON: So once you get a big thick heavy biofilm in that case, it's going to be really hard to get it out of there. And studies in our lab and other laboratories have shown that, you know, after about nine months, I'd say 80 to 90 percent of lens cases have bacterial contamination.
NEIGHMOND: Which can cause eye irritations, allergic reactions, and even infections. Ophthalmologist Jim Salz, with the American Academy of Ophthalmology, says hygiene is important at every step.
DR. JIM SALZ: You wash your hands for sure and you remove each contact and put it in the reservoir, and then you leave them overnight. And then in the morning you take them out, with clean hands again. And you wash your hands, take the contact and put it in your eye.
NEIGHMOND: And ideally, empty out the case completely.
ROBERTSON: Clean it, let it air dry and then refill it with some more solution. And every month or so, get a new case.
NEIGHMOND: And always use a sterile cleaning solution. A recent study in Great Britain found that some people were actually using fruit juice, butter and even beer to store and clean their contact lenses. That's an obvious don't. Another, says Salz, sleeping in your contacts.
SALZ: The risk of sleeping in contact lenses, the risk of getting a serious corneal ulcer is one in 1,000 patients. Whereas, if you take them out every day, it's one in 10,000 patients. So it's 10 times riskier to sleep in contacts then to take them out every day.
NEIGHMOND: And one of the biggest and often overlooked risks is water - the ocean, lakes, swimming pools, hot tubs, even tap water - places where potentially dangerous organism like amoebas can lurk.
Researcher Danielle Robertson.
ROBERTSON: These amoebas can actually bind to your lenses and then you go back, you store your lenses in the lens case, you have an old lens case, there's lots of bacteria in it, these guys are going to feed on that, like sitting down at the table at Thanksgiving and they're just going to grow and flourish.
NEIGHMOND: Putting you at risk for an infection so severe it can cause permanent visual damage and even blindness. So don't cavalierly clean and store your contacts, make sure you adhere to all those simple, little, but critically important, steps.
Patti Neighmond, NPR News.
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