Contact lens fungus link to blindness

CONTACT lens wearers have been warned about a new fungus that can lead to blindness, after an investigation found that 200 people in the United States and the Far East have contracted the condition.

The infection - called fusarium keratitis - has prompted the withdrawal of one type of lens cleaning solution used by many of those affected.

But people with poor contact lens hygiene also appear to be at increased risk of catching the infection, which was described as "the most severe complication related to contact lens wear" by researchers.

Several of those infected in the outbreak are expected to need corneal transplants to fully restore their sight.

Experts said it was rare in Britain, but advised anyone travelling to hot and humid climates, where the fungus is more common, to switch to daily disposable contact lenses to avoid the risk associated with wearing longer-lasting lenses.

In a paper published in today's edition of the Journal of the American Medical Association, scientists at the Singapore Eye Research Institute (SERI) said the three outbreaks "suggest that this phenomenon may be part of a global problem, with serious implications for millions of lens wearers worldwide".

They said the infection rate in Singapore - with 2.35 cases out of every 10,000 people wearing contact lenses was an "astounding figure".

They continued: "We believe that Singapore is facing a new and unprecedented outbreak of fusarium keratitis and that this is the first time that such an outbreak has been reported among contact lens wearers anywhere in the world.

"By highlighting this serious outbreak of fusarium keratitis among contact lens wearers in Singapore, we hope to alert physicians and other eye-care clinicians worldwide to maintain a high index of suspicion for fungal infections."

The researchers said 7.4 per cent of those infected in Singapore needed "urgent surgical intervention to treat acute corneal perforation" or to stop this from happening. "It is likely that additional cases may require subsequent corneal transplantation for residual scarring."

Nearly all patients wore soft, disposable contact lenses and just under two-thirds reported using a cleaning fluid called ReNu with MoistureLoc.

This was withdrawn from the market worldwide this year, with the manufacturer, Bausch & Lomb, saying some part of the formula "may be increasing the relative risk of fusarium infection in unusual circumstances".

However, Professor Roger Buckley, a former president of the British Contact Lens Association, has said he believes the apparent link with the MoistureLoc fluid was simply because it was so commonly used in Singapore, adding "it is likely that the cause will be found elsewhere".

To date, fungal keratitis has been rare in the UK. ISD Scotland, which collates statistics from the NHS and Scottish Executive, said it did not have any relating to the condition. Donald Cameron, a leading Edinburgh optometrist, said he had never seen a single case in 30 years, while Dr Stuart Roxburgh, a leading eye specialist at Ninewells Hospital in Dundee, said he saw about one case in every two years.