Outbreak of preventable eye infection in contact lens wearers

September 21, 2018, University College London
Credit: CC0 Public Domain

A new outbreak of a rare but preventable eye infection that can cause blindness, has been identified in contact lens wearers in a new study led by UCL and Moorfields Eye Hospital researchers.

The research team found a threefold increase in Acanthamoeba keratitis since 2011 in South-East England.

Reusable contact lens wearers with the are more likely to have used an ineffective contact lens solution, have contaminated their lenses with water or reported poor contact lens hygiene, according to the findings published today in the British Journal of Ophthalmology."This infection is still quite rare, usually affecting 2.5 in 100,000 contact lens users per year in South East England, but it's largely preventable. This increase in cases highlights the need for contact lens users to be aware of the risks," said the study's lead author, Professor John Dart (UCL Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust).

Acanthamoeba keratitis is an eye disease that causes the front surface of the eye, the cornea, to become painful and inflamed, due to infection by Acanthamoeba, a cyst-forming microorganism.

The most severely affected patients (a quarter of the total) have less than 25% of vision or become blind following the disease and face prolonged treatment. Overall 25% of people affected require corneal transplants to treat the disease or restore vision.

Anyone can be infected, but contact lens users face the highest risk, due to a combination of increased susceptibility to infection, for reasons not fully established, as a result of contact lens wear and contamination of lens cases.

The researchers collected incidence data from Moorfields Eye Hospital, from 1985 to 2016. They found an increase dating from 2000-2003, when there were eight to 10 cases per year, to between 36-65 annual cases in the past few years. As Moorfields treats more than one in three cases of the disease in the UK, the researchers expect their findings are relevant to the UK more broadly.

Alongside these findings, they conducted a case-control study of people who wear reusable 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.

The case-control study included 63 people with Acanthamoeba keratitis and 213 without. They all completed a questionnaire, from which the researchers found that the risk of developing the disease was more than three times greater amongst people with poor contact lens hygiene, people who did not always wash and dry their hands before handling their lenses, those who used a lens disinfectant product containing Oxipol (now phased out by the manufacturer), and for people who wore their contacts while in swimming pools or hot tubs. Showering and face washing while wearing contact lenses are also likely to be risk factors.

Acanthamoeba is more commonly found in the UK than in other countries, likely due to higher levels found in domestic (as opposed to mains) water supplies, so that water contamination of contact lenses is of particular concern in the UK.

The researchers say the current outbreak is unlikely to be due to any one of the identified risk factors in isolation.

"People who wear reusable contact lenses need to make sure they thoroughly wash and dry their hands before handling contact lenses, and avoid wearing them while swimming, face washing or bathing. Daily disposable lenses, which eliminate the need for contact lens cases or solutions, may be safer and we are currently analysing our data to establish the risk factors for these," said Professor Dart.

"We now need to share this information as widely as possible with clinicians, contact lens practitioners and wearers, a strategy that has proved effective in the past in decreasing the incidence and burden of this severe eye infection," said co-author Dr. Nicole Carnt, who completed the study at Moorfields before moving to the University of New South Wales."This research confirms what those of us affected by Acanthamoeba keratitis have suspected for some time: that incidences of this awful, life-changing infection are on the increase, and there's more that should be done to prevent people from losing their sight to Acanthamoeba keratitis," said Irenie Ekkeshis, who is part of Acanthamoeba Keratitis Patient Support Group UK."It is absolutely imperative that regulators and those working in the optical sector take the findings seriously, and use the recommendations to take immediate and urgent action on prevention. Contact lenses are medical devices and should be supplied with warnings regarding safe use."

Explore further: Data analysis finds lower risk of infection with LASIK than with contacts over time

More information: Nicole Carnt et al, Acanthamoeba keratitis: confirmation of the UK outbreak and a prospective case-control study identifying contributing risk factors, British Journal of Ophthalmology (2018). DOI: 10.1136/bjophthalmol-2018-312544

Related Stories

Data analysis finds lower risk of infection with LASIK than with contacts over time

April 21, 2017
Which causes fewer eye infections - contact lens wear or LASIK surgery? While traditionally contacts were thought to be safer than a surgical procedure, an analysis by ophthalmologists from the Hamilton Eye Institute at the ...

Lens surface, care solution affect adhesion of Acanthamoeba

March 4, 2016
(HealthDay)—Both rigid gas permeable (RGP) contact lens surface and multipurpose contact lens care solutions (MPSs) impact adhesion rates of Acanthamoeba castellanii (AC) trophozoites, according to a study published in ...

Most contact lens wearers take chances with their eyes: CDC

August 20, 2015
(HealthDay)—Most contact lens wearers close their eyes to safety recommendations, a new U.S. government study finds.

Hygiene practices affect contact lens case contamination

January 28, 2015
Contact lens wearers who don't follow certain hygiene habits have increased bacterial contamination of their contact lens cases, reports a study in the February issue of Optometry and Vision Science, official journal of the ...

FDA approves contact lenses that shade the sun

April 13, 2018
The lives of contact lens wearers just got a whole lot easier.

Recommended for you

Researchers report vision-based neurotransmitter events for the first time

November 27, 2018
How does vision work, and what happens in the brain during the process? As simple as this question may sound, it has yet to be scientifically clarified. Dr. Valentin Riedl of the Technical University of Munich (TUM) and his ...

Minimally invasive retinal detachment has better outcomes, clinical trial findings

November 26, 2018
A minimally invasive treatment for retinal detachment gives patients sharper vision, less distortion and reduced side-effects, according to the findings of a randomized controlled trial performed at St. Michael's Hospital ...

Scientists combine technologies to view the retina in unprecedented detail

November 14, 2018
By combining two imaging modalities—adaptive optics and angiography—investigators at the National Eye Institute (NEI) can see live neurons, epithelial cells, and blood vessels deep in the eye's light-sensing retina. Resolving ...

Eyepatch with dissolvable needles used to treat eye disease

November 12, 2018
A team of researchers affiliated with several institutions in Singapore has developed an eyepatch with dissolvable needles for use in treating eye diseases. In their paper published in the journal Nature Communications, the ...

Calcifications in the eye increase risk for progression to advanced AMD by more than six times

November 8, 2018
Calcified nodules in the retina are associated with progression to late stages of age-related macular degeneration (AMD). Experts from Queen's University Belfast, working in partnership with the University of Alabama of Birmingham ...

Traditional glaucoma test can miss severity of disease

November 8, 2018
The most common tests for glaucoma can underestimate the severity of the condition by not detecting the presence of central vision loss, according to a new Columbia University study.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.