This infection, called Fusarium keratitis, involves a swelling and inflammation of the cornea that can be harmful to the structure of the eye and the patient's vision. In many cases, scarring is so severe that patients must undergo full corneal transplant.
Now, a new study finds 34 cases of the infection appearing over the past two years in the Miami area alone, compared to just five cases occurring between 1982-1992.
These cases may be just the tip of the iceberg in a worldwide problem, one expert said.
"These articles are just a few case reports representative of the Fusarium corneal infection epidemic in the United States and other parts of the world," said Dr. Robert Cykiert, a clinical associate professor of ophthalmology at New York University School of Medicine.
Cykiert was not connected to the new study, which appears in the June 12 online edition of the Archives of Ophthalmology.
Some 30 million Americans wear contact lenses, and about 2.3 million used MoistureLoc, according to the Associated Press.
Bausch & Lomb also makes ReNu MultiPlus, ReNu Multi-Purpose and various generic brands.
In the new study, lead researchers Dr. Eduardo C. Alfonso and colleagues at the University of Miami's Miller School of Medicine, reported on 34 cases of fungal keratitis, from January 2004 to April 2006, seen in people who wear soft contact lenses.
Alfonso noted that at the University of Miami there were only three cases of fungal keratitis linked to contact lenses between 1969 and 1977, two between 1977 and 1982, and five between 1982 and 1992.
A review of the patients' medical records showed that none of them had a history of disease that would predispose them to fungal eye infections. Twelve of 13 patients who could identify the type of contact lens solution they used said that they used some type of ReNu brand solution.
Two had used ReNu MoistureLoc, the solution implicated in recent Fusarium outbreaks in the United States and Singapore. Nine others used the ReNu brand without specifying a particular product.
After being diagnosed with fungal keratitis, patients were treated for over two months with topical or systemic antifungal medication. Two patients required surgery.
Alfonso's team found that those treated earlier had a faster recovery and did not need surgery. "Based on treatment experience in this series, it is our clinical impression that earlier correct diagnosis with institution of proper specific antifungal therapy resulted in a speedier resolution of the keratitis," the authors said.
Based on their findings, the authors concluded that "Ulcerative keratitis in a soft contact lens wearer should suggest possible Fusarium or other fungal species in addition to bacteria, parasites or viruses as causative organisms. Clinicians should conduct the necessary clinical and laboratory investigations to establish a specific diagnosis promptly to initiate the most specific, efficacious therapy."
In a second report in the same journal issue, Dr. Maria D. Bernal and colleagues at the University of California, San Francisco, reported on four more cases of Fusarium infection among soft contact lens wearers seen during five weeks in early 2006.
"Our report strongly suggests that the current cluster represents an unusual spike over the background incidence of Fusarium keratitis seen during the prior 30 years at our institution," the authors wrote.
"We, other laboratories, and the Centers for Disease Control and Prevention (CDC) are currently investigating the fungicidal properties of the contact lens solutions used by these patients and the genotype characteristics of the Fusarium isolates in an effort to determine the underlying cause of the current apparent outbreak and whether the Fusarium species from these cases originate from a common strain," they concluded.
According to the CDC, there have been over 130 documented cases in the United States in the last six months, Cykiert said. "Approximately 30 percent of the cases have required corneal transplantation. There are probably many more that have not been reported to the CDC, or have not been tabulated yet. Many more patients will need corneal transplants in the future, since these infections often leave severe scarring," he said.
The CDC and Bausch & Lomb have agreed that the infections are directly related to the use of Bausch & Lomb MoistureLoc contact lens solution, Cykiert said. "Somehow, this solution is not adequately killing or eradicating this species of fungus from contact lenses and/or contact lens cases. Bausch & Lomb has appropriately recalled all MoistureLoc solution worldwide," he said.
Cykiert said many consumers might also be wondering if ReNu MositureLoc might be sold in chain stores in a generic form.
"For example, I am fairly certain that Bausch & Lomb manufactures Wal-Mart contact lens solutions," he said. "There has not been any mention, to my knowledge, as to whether the generic contact lens solutions are equivalent to or the same as MositureLoc."
In response, Bausch & Lomb spokeswoman Meg Graham said ReNu MoistureLoc has never been available at Wal-Mart or any other outlet under another name.
"ReNu MoistureLoc was never sold as a private-label item," said Bausch & Lomb spokeswomen Meg Graham. Any supply of the product at these stores was part of the announced recall, she added.