If you wear contact lenses or are contemplating the idea, there are a few things you must always bear in mind when handling them.
Improper handling can introduce bacteria and germs into the eye, and eye infections can lead to permanently impaired vision, blindness, and in rare cases - death.
Here are the four most dangerous mistakes contact lens wearers make, and what you can do to avoid them.
Mistake #1: Sleeping with your lenses on
DANGER! Broken lens fragments in your eye
If you sleep without removing your contact lenses, you'll find it more difficult to do so the next morning.
"And if you pinch the lens too tightly, you risk breaking it and getting a fragment stuck in your eye." says Dr Lee Hung Ming, medical director of Parkway Eye Clinic at Gleneagles Hospital.
If it's not removed promptly by a doctor, the fragment can scratch your cornea or cause a bad infection.
Eye doctors recommend you do not sleep with your contacts. But in the event that you do (like after a drunken night out), lubricate your lenses with saline or eye drops before removing them.
This allows your lenses to come off more easily.
Mistake #2: Rinsing your lenses with tap water
DANGER! A cornea-eating worm in your eye
Acanthamoeba can get in your eye if you rinse your contacts with tap water instead of saline.
"This worm is found in many places, including tap water," says Dr Por Yong Ming, consultant eye surgeon at Jerry Tan Eye Surgery.
And when you rinse using such water, the parasite may end up on your lens. It can cause a very severe eye infection and even blindness, says Dr Lee.
If you really have to rinse your lenses and saline solution is unavailable, use distilled bottled drinking water (not mineral water).
Also, use daily disposable ones if you swim with your lenses on, says Raymund Song, senior professional service manager at Bausch and Lomb.
Mistake #3 Wearing your lenses for longer than prescribed
DANGER! Germ-infestation in your eye
If you've been wearing your two-week contact lenses for months, they're probably already germinfested.
The more germs accumulate, the more the risk of severe infection increases.
If you absolutely need to wear your lenses a few extra days (note: not weeks), Elliott Myrowitz, chief of optometric services at Johns Hopkins University's Wilmer Eye Institute, has this advice:
"After you pop them out, douse your lenses with an all-purpose cleaning solution and rub them with clean fingers for at least 10 seconds. Then rinse with more cleaning solution before storing them in your case with fresh solution.
"Also, wipe your lens case with tissue soaked in lens-cleaning solution, and air-dry the case at least once a week."
Mistake #4: Using "no-rub" solutions
DANGER! Severe corneal infection
"No-rub" multipurpose disinfection solutions (MPDS), which claim to be able to disinfect and clean contact lenses without the need for "rubbing", may be convenient.
But in 2008, the Centers for Disease Control and Prevention in the US found that two outbreaks of severe eye infections were linked to the use of "no-rub" MPDS.
Bacteria, mould and yeast remain on the surface of your lenses if you do not rub while cleaning them, says a study published in the Journal of Optometry and Vision Science.
These deposits allow allergy and infection-causing germs to accumulate on your lens surface.
Use the "rub and rinse" method even if you are using a "no-rub" solution.
Spend 10 seconds - only 10! - rubbing each of your lenses (see tips on next page) to reduce the risk of eye infections.
5 steps to germ-free lenses
Use this five-step process to keep your contact lenses germ-free and clean.
1. Wash your hands with a mild soap, says optometrist Raymund Song.
2. Clean the lens by placing it on your palm. Squeeze three drops of multipurpose solution on each side of the lens. Gently rub each side for 20 seconds.
3. Rinse each side of the lens for five seconds with the solution.
4. Place the lenses in a clean lens case and fill with multipurpose solution. Soak them for four hours.
5. At least once a week, wipe the case with a clean tissue soaked with the solution. Let the case air-dry.
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Leonard Lai is a Contributing Writer with Men’s Health magazine by SPH Magazines.
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