2 reasons why you should never store your contact lenses in water

Medically reviewed by Jakub Odcházel, DiS., Chief Optician, on 7 Nov 2018. Written by Lentiamo

It's likely happened to everyone who wears contact lenses. You've out of contact lens solution on holiday or have simply forgotten to order a new bottle and don't have extra on hand.

You've probably wondered if you can safely use tap water instead of contact lens solution. Our advice? Never store contact lenses in water.

Here’s why you should never clean or store your contacts in water, not even temporarily.

1. Tap water doesn’t have the qualities of a solution

Water won’t clean or disinfect lenses: Water won't remove debris, lipids, or protein deposits from lenses.
Water is not sterilised: Even the cleanest tap water still contains dangerous viruses, fungi and microorganisms, the most dangerous of them being acanthamoeba.
Tap water can harm lenses themselves: Water interferes with the osmotic balance of contacts when they're kept in water. This leads to lenses changing their shape, resulting in improper fit and discomfort.
Water does not contain lubricants: Water won't moisturise contact lenses properly. This makes wearing them very uncomfortable and irritating.

2. Acanthamoeba keratitis bacteria are extremely harmful to your eyes

What is acanthamoeba? Pronounced a·can·tha·moe·ba, acanthamoeba is a genus of amoeba that causes a very serious disease of the cornea that can lead to blindness.

Acanthamoeba is a microbe that is very common in the environment, including tap water. It can affect anyone, however, 80–90 % of patients affected by acanthamoeba are contact lens wearers. It is very persistent and can endure temperatures over 100 degrees for a short time. This means it can’t be destroyed by boiling. Acanthamoeba feels at home where the environment is warm and humid.

Acanthamoeba flourishes in water pipes or anywhere there’s limescale, for example in filters or water taps. The rough surface of deposits is the ideal breeding ground for acanthamoeba.

Interestingly, heated water is actually more dangerous than cold. Why is acanthamoeba so dangerous? When it gets into the eye, it causes acanthamoeba keratitis, a disease that can have catastrophic results, including blindness. It can occur more easily than we think. If acanthamoeba comes in contact with a lens, it will easily grip to the surface. Then all it takes is the tiniest damage of the cornea (for example while putting a lens in or taking it out), and the door to an infection is open.

How to recognize the symptoms?

Acanthamoeba attacks the cornea, which doesn’t contain veins and is less capable of reacting than other organs. In an advanced stage, it causes the formation of corneal ulcers, which can lead to the penetration of the cornea itself.

The symptoms usually are:

Severe headaches
Excessive tearing
Swelling
Eye twitching
Sensitivity
Foreign body sensation
Poor vision

The incubation period is approximately two weeks. The healing process is long and can take up to several weeks or months. Even after healing, eyesight is often weaker. In more acute manifestations, it can even lead to blindness. If you suspect you might have acanthamoeba keratitis, set a pair of your lenses aside for your doctor to examine and bring the case that you had kept them in.

How can you prevent all this?

Follow a few rules, the most important being never store your contact lenses in tap water. What else can you do?

Follow these general rules:

• Do not use tap water, not even for rinsing your contacts or case.
• Contact lenses should be cleansed with the rub and rinse method.
• Never refill old solution in a case with a new one.
• Don’t forget to replace your case every three months.
• And if you go for a swim, whether in the sea, a river or a lake, use dailies and throw them away at the end of the day.