Reusable contact lenses increase risk of sight-threatening eye infection: study

SYDNEY, Sept. 27 (Xinhua) -- Those wearing reusable contact lenses are nearly four times as likely to develop a rare sight-threatening eye infection as those who use daily disposables, according to a study published in the Ophthalmology journal.

Conducted by researchers from University of New South Wales (UNSW), University College London and Britain's Moorfields Eye Hospital, the study released in August identifies multiple factors that increase the risk of a severe eye infection called Acanthamoeba keratitis (AK), which can cause blindness.

The case control study involved over 200 patients of the Moorfields Eye Hospital and found that people who wore reusable soft contact lenses had 3.8 times the odds of developing AK, compared to people who wore daily disposable lenses.

Among daily disposable lense wearers, showering while wearing lenses increased the odds of AK by 3.3 times, while wearing lenses overnight increased the odds by 3.9 times. Reusing daily disposable lenses increased the infection risk by 5.4 times.

The researchers further estimated that 30-62 percent of cases in Britain, and potentially in many other countries, could be prevented if people switched from reusable to daily disposable lenses, highlighting the need for eye hygiene to be taken seriously.

"Previous studies have linked AK to wearing contact lenses in hot tubs, swimming pools or lakes, and here we have added showers to that list, underlining that exposure to any water when wearing lenses should be avoided," Nicole Carnt, lead author and associate professor of UNSW Medicine and Health, said in a statement on Tuesday.

Carnet noted that public pools and coastal authorities could help reduce this risk by advising against swimming when wearing contact lenses.