An outbreak of a rare but preventable eye infection, that can cause blindness, has been identified in contact lens wearers in the UK, scientists say. 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, according to the findings published 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 John Dart, a professor at the University College London in the UK. 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. Researchers found a threefold increase in Acanthamoeba keratitis since 2011 in South-East England. The most severely affected patients (a quarter of the total) have less than 25 per cent of vision or become blind following the disease and face prolonged treatment. Overall 25 per cent 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. "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,\u201d said Dart. \u201cDaily 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," he said.