Dr. Arshad received her PhD from the School of Optometry and Vision Science, UNSW, Sydney, Australia in 2020. After graduating with a BSc(h) Optom in 2011 from Pakistan, Dr. Arshad completed her M.Phil thesis in 2015. Dr. Arshad has worked as a casual academic and teaching fellow and is currently completing a Faculty of Science, Writing Scholarship at UNSW, Sydney.
Summarising the PhD work of Memoona Arshad and supervisors, Jacqueline Tan, Nicole Carnt and Fiona Stapletons on the water-contact behaviour of contact lens wearers and the contamination of lens cases in the presence of ‘no water’ stickers.
Contact with water is a known risk factor for Acanthamoeba keratitis.1-4 Although practitioners report routinely informing patients about avoiding water when wearing or handling their lenses, this advice does not always translate into compliant practices.
A study was designed to examine the effect of placing ‘no water’ reminder stickers on contact lens cases. Did visibility of the message change the water habits of wearers, and were there any measurable differences in microbial contamination of the contact lens case?
The results of the first part of the study regarding contact lens wearer water habits were presented at the BCLA conference, Manchester, UK, in June 2019. The data on case contamination were shared in a poster at the International Cornea and Contact Lens Congress, Noosa, Australia, in October, 2019. Examples of ‘no water’ stickers are shown below:
In a prospective, masked, randomised controlled trial, 200 contact lens wearers were randomised to either receive a storage case with a “no water” sticker (test group) or without (control group). Participants completed a contact lens hygiene questionnaire at baseline and after 6 weeks. Overall water-contact behaviour was quantified based on factors such as showering, swimming, use of wet hands and use of tap water during the participants contact lens care wear (score: 0=excellent, 8=poor).
At baseline, the median (Inter quartile range; IQR) water-contact score was 1(3) and 2(2) in the test and control group respectively and there were no differences between groups for overall water-contact behaviour score or individual behaviours. At the follow-up visit, the median (IQR) water-contact score was 1(1) and 1(2) in the test and control group respectively and both groups differed significantly (p=0.005; one-way ANCOVA)). No significant differences were found for individual water-contact behaviours in both groups.
The inclusion of “no water” stickers on the contact lens case improved the overall water contact behaviour score. Refining the messaging on the “no water” stickers may help to reinforce water avoidance for individual water-contact behaviours such as showering or swimming in lenses.
Overall microbial contamination (using a validated bacterial ATP assay) and endotoxin levels (using a LAL assay) toxins of contact lens cases were also established in the same test (95 participants who used “no water” stickers on their contact lens cases), and control (93 who did not) groups. Both groups were provided with written instructions. Endotoxin is the by-product of gram negative microbes, which are water bourne. The endotoxin levels were significantly reduced in the test group at the follow-up visit, compared to the control group when controlling for the baseline measurements (p=0.02). Furthermore, the overall water exposure score was significantly lower in the test group compared to the control group at the follow-up visit, controlling for the baseline measurements (p=0.005).
Conclusion # 2
The inclusion of “no water” stickers on contact lens storage cases reduced the endotoxin levels in lens case contamination and improved the overall water-contact behaviour of contact lens wearers.
Overall take away points
These results show that an intervention as simple as a sticker on contact lens cases can help change contact lens wearer behaviour and result in a measurable difference in case endotoxin levels. It is known that to maintain compliant behaviours that multiple reminders over time are more effective than any one single intervention.5 The addition of a visual reminder is a good example of a repeated reminder a patient can see every time they go to use their contact lenses, and is likely a useful additional tool to supplement standard patient education messages to help encourage compliant water contact behaviour.
- Carnt N, Hoffman JJ, Verma S, et al. Acanthamoeba keratitis: confirmation of the UK outbreak and a prospective case-control study identifying contributing risk factors. The British journal of ophthalmology. 2018.
- Ibrahim YW, Boase DL, Cree IA. How Could Contact Lens Wearers Be at Risk of Acanthamoeba Infection? A Review. Journal of optometry. 2009;2(2):60-66.
- McKelvie J, Alshiakhi M, Ziaei M, Patel DV, McGhee CN. The rising tide of Acanthamoeba keratitis in Auckland, New Zealand: a 7-year review of presentation, diagnosis and outcomes (2009-2016). Clinical & experimental ophthalmology. 2018;46(6):600-607.
- Randag AC, van Rooij J, van Goor AT, et al. The rising incidence of Acanthamoeba keratitis: A 7-year nationwide survey and clinical assessment of risk factors and functional outcomes. PloS one. 2019;14(9):e0222092.
- Cherry MG, Brown JM, Bethell GS, Neal T, Shaw NJ. Features of educational interventions that lead to compliance with hand hygiene in healthcare professionals within a hospital care setting. A BEME systematic review: BEME Guide No. 22. Med Teach. 2012;34(6):e406-420