Reusable contact lenses 'more than triple risk' of rare eye infection


People who use reusable contact lenses are nearly four times more likely than those who use daily disposables to develop a rare type of eye infection.

Researchers from University College London have identified multiple factors that increase the risk of Acanthamoeba keratitis (AK), a condition that results in inflammation of the cornea, including reusing lenses or wearing them overnight or in the shower.

"In recent years we have seen an increase of Acanthamoeba keratitis in the U.K. and Europe, and while the infection is still rare, it is preventable and warrants a public health response," said lead author Professor John Dart. "Contact lenses are generally very safe but are associated with a small risk of microbial keratitis, most commonly caused by bacteria, and which is the only sight-threatening complication of their use. Given that an estimated 300 million people across the globe wear contact lenses, it is important that people know how to minimise their risks for developing keratitis."

For the study, researchers recruited over 200 patients who completed a survey, including 83 people with AK. They found that those who wore reusable soft contact lenses (such as monthlies) had 3.8 times the odds of developing the condition, compared to people who wore daily disposable lenses. Showering with lenses increased the odds of AK by 3.3 times, while wearing lenses overnight increased the odds by 3.9 times.

Accordingly, Professor Dart urged contact lens wearers to abide by hygiene guidelines.

"Contact lens packaging should include information on lens safety and risk avoidance, even as simple as 'no water' stickers on each case, particularly given that many people buy their lenses online without speaking to a health professional," he added. "Basic contact lens hygiene measures can go a long way in avoiding infections, such as by thoroughly washing and drying your hands before putting in your lenses."

Full study results have been published in Ophthalmology.