Raising awareness of the dangers of tap water for contact lens wearers
Dr Nicole Carnt | GR000183-6
9 January 2020 (last updated 29 September 2022)
We’re funding a campaign to raise awareness of correct contact lens hygiene and the dangers of developing Acanthamoeba keratitis (AK) through exposing contact lenses to tap water.
Update: further work on AK reaffirms potential risks
A study supported by Moorfields Eye Charity and recently published in Ophthalmology, identifies multiple factors that increase the risk of AK, which includes wearing them in the shower.
The study indicated that people who wore reusable soft contact lenses (such as monthlies) had 3.8 times the odds of developing AK, compared to people who wore daily disposable lenses. Showering with lenses increased the odds of AK by 3.3 times.
Previous studies have linked AK to wearing contact lenses in hot tubs, swimming pools or lakes, and here we have added showers to that list, underlining that exposure to any water when wearing lenses should be avoided.
Nicole Carnt, associate professor, UNSW, Sydney, UCL Institute of Ophthalmology and Moorfields Eye Hospital
With this further analysis, the researchers estimated that 30-62% of cases of AK in the UK, and potentially in many other countries, could be prevented if people switched from reusable to daily disposable lenses.
AK is a rare but sight-threatening infection of the clear front of the eye (cornea). It is an eye infection caused by a microscopic organism called Acanthamoeba, which is commonly found in water, soil and air. It usually occurs when contact lenses are contaminated with tap water.
Around a quarter of patients with AK lose significant vision as a result of infection.
Over 85% of cases occur in contact lens wearers, who are generally young and otherwise healthy individuals.
A recent study by Professor John Dart, consultant ophthalmologist at Moorfields Eye Hospital, has shown that the risk of developing AK is increased three-fold by:
- poor contact lens hygiene
- contamination with water
- sleeping with reusable contact lenses
Most people who wear contact lenses aren’t aware of this.
What is Acanthamoeba keratitis (AK)?
Acanthamoeba keratitis (AK) is an infection of the cornea, caused by a microscopic organism. It is very rare, extremely painful, and can cause permanent visual impairment or even sight loss.
AK is usually found in bodies of water such as rivers, swimming pools. It can even be found in soil and air.
Little is known about this condition and it can be difficult to diagnose because many of the symptoms are similar to other microbial corneal infections.
Around 85 per cent of AK cases are associated with contact lens wear
AK affects 125 people per year in the UK
Treatment involves eye drops with antimicrobial effects, as well as anti-inflammatory and pain relief eye drops. Frequently antibiotics are required to treat bacterial co-infection or prophylaxis.
Finding a solution
Building upon a case control study into the genetic and environmental risk factors for AK, researchers at Moorfields Eye Hospital, together with patients with AK, worked to encourage healthy contact lens use through a number of avenues including a social awareness publicity campaign.
Videos from the NIHR Biomedical Research Centre at Moorfields and the UCL Institute of Ophthalmology also highlighted best practice for contact lens use.
The campaign gained good traction. Heavy traffic from the optical media (including Contact Lens Spectrum in the US) prompted an article in a national newspaper and two primetime radio slots.
The campaign also reached a large number of people through Moorfields’ own digital channels.
The first two weeks of the campaign saw:
- a 15% increase in page views of the Moorfields website
- a 136% increase in YouTube views
- 70 new Facebook likes
- 60 new Twitter followers
- 21 new LinkedIn likes
Through continued engagement, the impact of a number of research and patient engagement activities has ensured that these successes continue to be built upon.
This includes publication of a patient information leaflet, patient focus and support group meetings and public awareness campaigns including a BBC news interview (April 2017) where a former Moorfields patient with AK continues to advocate greater awareness of the risks of AK.
Dr Nicole Carnt
Corneal disease | Education and training | Patient experience | Public/patient engagement