New Australian research has shown that infographics on contact lens cases can improve behaviour to avoid water-related corneal infections, in findings that challenge common assumptions about patients and lens hygiene habits.
The study, conducted at the University of New South Wales, aimed to determine the effect of ‘no water’ lens case stickers on patient behaviour and storage case contamination.
UNSW School of Optometry and Vision Science PhD candidate Ms Memoona Arshad, who performed the study, said a motivating factor for the study was frequent use of water-related imagery to indicate freedom from dryness. Marketing material also promotes spectacle independence and infers patients can participate in activities such as swimming or showering with lenses inserted.
“These behaviours are well established risk factors for corneal infection, particularly Acanthamoeba keratitis, yet water contact is often not discussed with contact lens wearers,” she said.
Arshad conducted the 18-month randomised, double masked, interventional controlled trial with UNSW Scientia research fellow and senior lecturer Dr Nicole Carnt, Professor Fiona Stapleton and Dr Jacqueline Tan. The study was an investigator led project funded by Alcon.
In total, 200 daily lens wearers were randomised to either receive a storage case with a ‘no water’ sticker (test) or without the sticker (control). Both groups received written compliance information and participants completed a self-administered lens hygiene questionnaire at baseline and after six weeks.
Microbial analysis of used storage cases, collected at both study visits, was conducted using ATP and limulus amebocyte lysate (LAL) assays for overall microbial contamination and endotoxin levels, respectively. A one-way ANCOVA and multiple logistic regression determined the change in water-contact behaviours and storage case contamination over time.
After six weeks, the research team found the overall water exposure score and endotoxin levels reduced significantly in the test group compared with the control group.
Carnt said the findings challenge a preconception among some practitioners that many contact lens wearers are unwilling to adapt their behaviours.
She also said there is a view that because diseases such as Acanthamoeba keratitis are rare, they are not worthy of heightened awareness – and wearers will refrain from wearing contact lenses if they are aware of it.
A recent study led by Carnt conducted across greater Sydney found 29% of domestic tap water supply samples (28/97) collected during summer and winter, were contaminated with free living Acanthamoeba. This meant exposure of contact lenses to contaminated water during showering or swimming without goggles increases the risk of contact lens-related disease.
“I find that people who suffer from Acanthamoeba keratitis have a real sense of injustice and wonder why this information wasn’t given to them. They also they want to tell other people to prevent it happening to them,” Carnt added.
One of those patients was UK woman Ms Irenie Ekkeshis, a highly compliant wearer with a marketing background who developed a severe case of the disease.
She was part of a 2013 trial where she crossed paths with Carnt at Moorfields Eye Hospital in London and came up with the idea of ‘no water’ warning stickers.
Together, they have lobbied and had them endorsed by the British Contact Lens Association, American Optometric and the Cornea and, as of last year, the Cornea & Contact Lens Society of Australia.
“Optometrists can get the stickers from the CCLSA, which have the right and left markings on them so they can put it on to the contact lens boxes, cases any paraphernalia,” she said.
“It’s a visual reminder for patients not to use water with contact lenses. We want to stress that it is important for people to wash their hands but they need to dry them as well. A lot of the time people think ‘well, we drink water and wash our face with it, so it must be sterile’, but microorganisms that are in it can have a devastating impact on the eye.”