Handle contact lenses with care

Nov 18, 2008 4:06 PM

If, like me, you're a contact lens wearer, you'll know how hard it can be to comply with all the advice from your optometrist. If you remove your lenses when you go swimming, you can't see the end of the pool. When you run out of saline solution—well, how bad can it be to use tap water to rinse your lenses instead?

Actually, it can be pretty bad. You risk a painful eye infection called amoebic keratitis, which can damage your sight if it isn't picked up and treated quickly. Cases of amoebic keratitis are increasing worldwide, probably because of the increase in people wearing contact lenses. It's caused by a microscopic bug called Acanthamoeba, which lives in soil and water, including swimming pools and tap water. Usually, it causes no problems. But if it contaminates your contact lens, it can infect your eyes.

A new study looked at the contact lens cases of 153 people in Tenerife, a Spanish island. Disturbingly, 66 in every 100 cases were contaminated with types of Acanthamoeba that can cause infection. The people most at risk were those wearing lenses designed to be worn for a month or longer. Daily disposable lenses were not a problem.

Previous studies (.pdf) in Scotland and in the north of Britain, found much lower levels of contamination. The researchers think people might be more at risk in hotter, dustier climates.

If you think that you're not at risk because your cleaning solution will kill the bugs, think again. The researchers found that commercial cleaning agents were not strong enough to kill the Acanthamoeba they found living in the lens cases.

What you need to know. It's worth taking the trouble to follow your optometrist's instructions in order to cut out the risk of damaging your eyesight. Always use contact lens cleaning fluid (and not tap water) to rinse your lenses. If you get sore, red eyes and you wear contact lenses, stop wearing them and see your doctor right away.

—Anna Sayburn, patient editor, BMJ Group

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