Wearers of soft contact lenses should be sure to practise good hygiene to prevent fungal eye infections, which are rare, but can be very serious, experts say.

Dusseldorf University Hospital and Germany’s National Reference Centre for Invasive Mycoses recently published a preliminary study on fungal eye infections in the Washington-based Journal of Clinical Microbiology.

In the study, 22 cases of corneal infections were analysed. In 15 of the patients, the infection was triggered by a fungus. Almost all of them wore soft contact lenses.

In the other seven cases, the symptoms were due to bacteria or more innocuous causes.

“Wearing soft contact lenses is the predominant risk factor,” says Dr Oliver Kurzai, chairman of the Department of Medical Microbiology and Mycology at the University of Wuerzburg.

Fungus can form when a contact lens case is kept in a place that’s too warm, for example. Using solution too often or for too long can also encourage fungal growth, as can wearing soft contact lenses for longer than recommended.

The risk of infection from hard contact lenses is much lower, though it’s not clear why, Dr Kurzai says. “Soft contact lenses fit more snugly on the eye and are much less oxygen-permeable, which could be the reason,” he notes.

In contrast to bacterial infections such as conjunctivitis, fungal infections can have severe consequences.

Contact lenses contaminated by mould fungus can lead to corneal infections with symptoms including red eyes, severe pain and impaired vision.

Treating fungal infections is difficult, Dr Kurzai says, because fungi are often resistant to available medicines.

In many cases, the only option is a cornea transplant. At worst, the eye must be removed and replaced with an artificial one made of glass.

The researchers point out that 22 cases aren’t enough for a conclusive study, and a larger database is needed.

“We therefore call on all ophthalmologists to send as many samples of suspected cases as possible to the National Registry of Mycotic Keratitis (in Dusseldorf),” Dr Kurzai says. The aim is to improve therapies and better identify pathogens.

The findings of the preliminary study weren’t surprising to the German Professional Association of Ophthalmologists (BVA), which has long warned of the dangers of improper hygiene with soft contact lenses and recommends hard lenses for medical reasons.

“Someone has finally done a specific study and published it,” says Dr Oliver Hoppe, who heads the BVA’s contact lens department. – dpa