Opinion

Why contact lenses and water don't mix

30 September 2020
Dr Nicole Carnt, UNSW SydneyNicole Carnt, Scientia Senior Lecturer, School of Optometry and Vision Science at UNSW Sydney, is helping to save people's sight by educating contact lens wearers on the risks of mixing their lenses with water.
 
If contact lenses are rinsed under the tap before being worn or exposed to other everyday sources of water, there is a very real risk of the lens and eye becoming infected with a microorganism found in tapwater that could lead to loss of sight.
 
The severe infection called acanthamoeba keratitis is estimated to affect 10-20 people a year in Australia. Of these, about two to four people a year will need a transplant at the front of their eye to regain vision and about two to five people will need treatment for more than a year.
 
Nicole Carnt is leading research on this topic, and has found that about one-third of bathroom sinks in greater Sydney contain acanthamoeba, meaning it is probably prevalent in other parts of the country too although research is yet to be undertaken in other regions.

Acanthamoeba are free-living protozoa (single-celled microorganisms) that feed on bacteria and cells at the front of the eye, the cornea. This leads to inflammation, disorganisation and destruction of the cornea, blocking vision.

The vast majority of acanthamoeba keratitis occurs in contact lens wearers, and the best way to avoid contracting it is to avoid exposing lenses to water. This means they should not be run under the tap, worn in the shower or worn while swimming.

Nicole’s professional standing and background in contact lens clinical trials led to the successful endorsement of a consumer concept of “no water” labels on contact lens packaging, now available in 5 countries including the UK, USA and Australia. An investigator led industry funded Random Controlled Trial of 200 contact lens wearers by Nicole’s team showed the “no water” symbol decreased water exposure behaviour and gram negative contamination of their contact lens storage cases.

Now, thanks to Nicole and her team, many new packs of contact lenses now carry “no water” warning stickers like the one below.

Sign warning contact lens users to avoid contact with water

Contact lens packs can clearly be marked reminding users of the dangers of exposing lenses to water. Cornea and Contact Lens Society of Australia

 

For more information, read Nicole's opinion piece at The Conversation. 

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