University College London| September 2018| Outbreak of preventable eye infection in contact lens wearers
A preventable eye infection has increased threefold since 2011. The infection -Acanthamoeba keratitis -is rare but preventable according to the lead author of the study, Professor John Dart, of UCL’s Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust.
The infection causes the front surface of the eye, the cornea, to become painful and inflamed, due to infection by Acanthamoeba, a cyst-forming microorganism
He has said that because of the risks, “this increase highlights the need for contact lens users to be aware of the risks.”
The findings of the study indicate that reusable contact lens wearers with the eye infection are more likely to have used an ineffective contact lens solution, have contaminated their lenses with water or reported poor contact lens hygiene.
The study examined data for South East England from Moorfields Eye Hospital from 1985 to 2016. Between 2000- 2003 there were 8- 10 cases reported each year, more recently there have been between 36-65 cases annually. As Moorfields treat a third of cases the research team expect the total number to be higher when data from across the country is taken into account.
In addition to the data, the researchers also conducted a case-control study of people who wear reusable contact lenses on a daily basis (although the disease is also associated with disposable lenses), comparing those who had a diagnosis of Acanthamoeba keratitis to those who had come in to Moorfields A&E for any other reason, from 2011 to 2014 (Source: UCL).
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The article has been published in British Journal of Ophthalmology
Background/aims Acanthamoeba keratitis (AK) is a chronic debilitating corneal infection principally affecting contact lens (CL) users. Studies were designed to test claims that the UK incidence may have increased in 2012–2014 and to evaluate potential causes.
Methods Annualised incidence data were collected from January 1984 to December 2016. Case-control study subjects were recruited between 14 April 2011 and 05 June 2017. Reusable CL users with AK were recruited retrospectively and prospectively. Controls were reusable CL users, recruited prospectively, with any disorder other than AK. Multivariable analysis of questionnaire data measured independent risk factors for AK.
Results The current outbreak of AK started in 2010–2011 with an incidence threefold higher than in 2004–2009. Risk factors for AK were: Oxipol disinfection, CLs made of group IV CL materials, poor CL hygiene, deficient hand hygiene, use of CLs while swimming or bathing, being white British, and for those in social classes 4–9.
Conclusion AK is a largely preventable disease. The current outbreak is unlikely to be due to any one of the identified risk factors in isolation. Improving CL and hand hygiene, avoiding CLs contamination with water and use of effective CL disinfection solutions, or daily disposable CLs, will reduce the incidence of AK. In the longer-term, water avoidance publicity for CL users can be expected to reduce the incidence further. Ongoing surveillance of AK numbers will identify changes in incidence earlier. Evaluation of Acanthamoeba contamination in end-user drinking water would contribute to our understanding of regional variations in the risk of exposure.
The full article can be requested by Rotherham NHS staff here