The following is a transcript based on an earlier draft of this week's podcast. As a result, the written transcript and the podcast may differ.

Greetings from the National Library of Medicine and MedlinePlus.gov

Regards to all our listeners!

I’m Dr. Donald Lindberg, the Director of the U.S. National Library of Medicine.

To listen to Dr. Lindberg's comments, click here

In What’s New in MedlinePlus this week, we have an update about Fusarium keratitis, a serious eye infection that has been linked to some contact lens cleaning products and poor contact lens hygiene.

For regular listeners, this is a follow-up to my podcast on May 15, 2006. This gave an early warning about cases of Fusarium keratitis in lens users. Subsequent events show the danger to be quite severe, with a number of affected cases needing surgery.

Two recent articles in the Journal of the American Medical Association (or JAMA) have heightened these public health concerns. The association of Fusarium keratitis with lens cleansing solutions has become more mysterious and compelling.

First some background. Fusarium keratitis occurs when this fungus causes an inflammation of the cornea, the front part of the eye. Fusarium is commonly found in soil and plants. Keratitis can be caused by bacteria, viruses and fungi.

In June, the U.S. Centers for Disease Control and Prevention (the CDC) confirmed 176 cases of Fusarium keratitis in 33 states. In July, JAMA reported an outbreak of Fusarium keratitis among 66 patients in Singapore. In both the U.S. and Singapore, the number of recent cases is significantly higher than the estimated annual incidence.

Similar to the Singapore cases, a new case-control study published in JAMA notes 69 percent of the U.S. patients with Fusarium keratitis used the ‘ReNu with Moisture Loc’ brand of contact lens cleaner. But some of the U.S. and Singapore patients used other contact lens cleaners. Some also admitted to rather poor contact lens hygiene practices, including overnight use of daily wear contact lenses and use of contact lenses past their replacement date.

Bausch & Lomb, which is located in Rochester, NY, recalled the U.S. distribution of ReNu with Moisture Loc products in April and its international distribution was halted in May.

The U.S. team of 18 researchers, which wrote one of the new JAMA articles, explains that 34 million Americans wear contact lenses. The team (which included scientists from the CDC) reports the risk of microbial keratitis among contact lens users is 80 times higher than among healthy persons who do not use contact lenses.

In a second, current JAMA article (which is a commentary on previous research), two San Francisco-based physicians emphasize the severity and long term effects of Fusarium keratitis.

Drs. Todd Margolis and John Whitcher explain that some Fusarium keratitis patients require corneal surgery or a cornea transplant, which mirrors what occurred in Singapore earlier this year. The authors add (and we quote) that for patients, ‘the visual outcome is often dismal’ (Unquote) and the long range effectiveness of therapeutic approaches remain uncertain.

Of course, the really interesting question is, how did this particular microorganism get associated with the particular eye preparation and seemingly not even with the earlier lens solutions of the same brand? One obvious possibility will no doubt occur to many listeners: namely, was the organism in the lens solution before the people put their lenses in it? This occurred to the public health investigators and the manufacturer too. So they examined and cultured the production facilities in the plant for Fusarium and also cultured unopened and unpurchased bottles of "RenNU with Moisture Loc". The result: no growth, no organisms found. So therefore no evidence that the product was or had become contaminated.

Following up on the same idea, the investigators carefully compared the detailed genetic features of many of the Fusaria strains that had been isolated from the eyes of affected patients. The result: all genetically different strains of Fusarium. Therefore, no support for the idea that the bottles had been contaminated at the manufacturing source.

Another obvious question naturally was, did the cases arise at a geographic place where the infectious agent, the Fusarium, is exceptionally common or for some reason more likely to be a problem? Here too the findings in this outbreak do not support the idea of a point source such as a clinic or service facility.

The outbreaks occurred in widely separated geographic locations: namely, South Florida, the San Francisco Bay area, Hong Kong and Singapore. In looking for common features in these locations that might possibly help explain the outbreaks, the authors could only note that the climates are all reasonably warm. San Francisco Bay area might not seem too tropical to visitors in June or July, but it shares with the other outbreak locations that weather below freezing is very rare. Hence the local soil at all these locations will contain Fusarium propagating naturally.

So the mystery still remains unsolved.

Drs. Margolis and Whitcher note a number of remaining questions, including these:

• is the cause of Fusarium keratitis really a specific brand of contact lens cleaner? if so, how did it act?
• is the outbreak more associated with contact lens hygiene?
• is the outbreak somehow associated with the use of ophthalmic corticosteroids by physicians?
• or, is the outbreak a result of a yet-to-be determined source?
  

Drs. Margolis and Whitcher note that speculation about the underlying causes of Fusarium keratitus will persist until there is more research and scientific evidence.

As interim steps, they recommend that contact lens users take these precautions:

• Avoid wearing contact lenses overnight, or when you sleep.
• Remove contact lenses at the first sign of eye irritation.
• Insist on seeing a medical professional if you experience contact lens-eye irritation.
  

We will provide more tips for contact lens users in a moment.

The authors also warn physicians to avoid prescribing ophthalmic corticosteroids, in combination with an antibacterial, when patients complain of acute red eyes. This used to be pretty common. But the authors now advise physicians to ask patients to undergo an eye exam quickly if they complain about contact lens irritation.

Drs. Margolis and Whitcher also refer to the increasing number of recent cases of Fusarium kertatitis as an ‘epidemic.’ For physicians and public health officials, the use of the term ‘epidemic’ is not a casual rhetorical assertion. An ‘epidemic’ is often perceived as having urgent national - and possibly international - public health implications.

The declaration of an ‘epidemic’ by public health officials often initiates higher profile national interventions to foster public awareness and to encourage more preventive actions.

Accordingly, Drs Margolis’ and Whitcher‘s concern about Fusarium keratitis raises a macroscopic question: when is an ‘epidemic’ at the tipping point when it is warranted and sensible to declare that it is a public health emergency?

If you or loved ones are contact lens wearers, are we at a moment when a much greater sense of urgency about Fusarium keratitis is appropriate?

JAMA’s collected articles about Fusarium keratitis this summer suggest the infection is a growing public health concern. We will keep you updated as developments unfold and note how public health officials respond.

A Web site from the U.S. Food and Drug Administration (which is accessible within MedlinePlus) provides timely tips to improve contact lens hygiene. The Web site includes links to the JAMA articles discussed above as well as additional background information about Fusarium keratitis.

For contact lens wearers, some of the FDA tips to prevent infection are:

• Wash your hands with soap and water, and dry (lint-free method) before handling contact lenses.
• Wear and replace lenses according to the schedule prescribed by a physician.
• Follow the specific lens cleaning and storage guidelines given by a physician and the solution’s manufacturer.
• Regardless of which cleaning/disinfecting solution you use, clean each contact lens and use what it called a "rub and rinse" lens cleaning method. This helps minimize the number of germs and reduces the chances of infection.
• Keep a contact lens case clean and replace it every 3-6 months.
• Remove the lenses and consult your doctor immediately if you experience symptoms such as redness, pain, tearing, increased light sensitivity, blurry vision, discharge or swelling.
  

To find the FDA’s Web site, type in: ‘contact lens’ in the search box on MedlinePlus’ home page. Then, click on ‘Eye Wear (National Library of Medicine).’ The site is called ‘Contact Lenses and Eye Infections (Food and Drug Administration).’ It is located in the ‘Related Issues’ section.

And please …. take some precautions if you wear contact lenses.

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It was nice to be with you….

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