Taking a dip while wearing contact lenses may seem harmless. But it isn’t at all. Doing so can result in irritation, eye infections and potentially sight-threatening conditions such as corneal ulcer. In fact, you shouldn’t even take a shower with them on.

“Contact lenses shouldn’t be exposed to any kind of water, including tap water and water in swimming pools, hot tubs, oceans and lakes. Lakes and rivers are most likely to host bacteria, but swimming pools and even tap water can harbour dangerous microbes including the Acanthamoeba organism, which causes a painful corneal infection that is difficult to treat and can cause permanent vision loss,” says Dr Leo Seo Wei, a senior consultant ophthalmologist at Mount Elizabeth Hospital.

She adds that the chemicals in swimming pools are more likely to irritate your eyes if you’re wearing contacts because they’re porous and absorb chemicals. Plus, water can wash away the eyes’ natural tear film, making them drier.

Can I at least sleep with contact lenses on?

No. The potential consequences aren’t worth it.

“It’s bad and unhealthy to sleep with contact lenses on. Your eye tissues need oxygen to function properly. When you’re awake, your opened eyes get oxygen from your tears and the air, but when’re you’re asleep, your eyelids are shut and there is less oxygen being transmitted to the corneas from the surrounding air,” says Dr Leo.

“Sleeping with them on prevents even more oxygen from getting to your eyes because the lenses act as physical barriers.”

She explains that when the eyes don’t get enough oxygen, a condition called corneal neovascularisation can occur: it’s when small blood vessels grow in a cornea to provide an oxygen supply to the area.

Wearing your contacts to sleep can also lead to redness in the eyes, pain and increased sensitivity to light. And if they tighten around the eyes, there may be tiny rips or tears on the corneas. This may increase the risk of an eye infection, inflammation or abrasions.

The worst thing, though, is that you can go blind.

“Sleeping with contact lenses on increases your risk for potentially blinding, nasty eye infections such as infective keratitis and corneal ulcers six- to eightfold.”

Can they get lost in my eyes?

There might have been times when your contact lenses went “missing”. The good news is that they can’t get lost in your eyes.

Dr Leo explains that the continuous nature of the conjunctiva (a lining from the inner surface of the eyelid) to the eyeball makes it impossible for anything to get behind the eye and become trapped.

“When contact lenses are missing, they may have dislodged from the corneas and become folded. They may be stuck under the eyelids and thus seem to have disappeared,” she says. She recommends seeking professional help from an eye doctor if you can’t retrieve them on your own.

I ran out of solution. Can I store them in water?

No. Please don’t anyhow. 

“Contact lenses should not be stored in anything other than contact lenses solution, and should be cleaned every time you take them out,” says Dr Leo.

“If you’re caught in a situation where you need to store your lenses overnight and don’t have any contact solution, you can use saline solution, distilled water and salt water.”

She, however, points out that while these alternatives are safer than tap water, there is still risk of infection.

And even if your contact lenses are BNIB, please don’t wear them if they’re expired.

“The expiry date indicates the last month and year that the container is considered free from contamination. Upon expiration, the solution in the package has an unstable pH and the risk of infection increases,” she says.