Bausch & Lomb's manufacturing process probably was not to blame for the outbreak of a serious eye infection in the US this spring, but the company's global recall of the ReNu with MoistureLoc product appears to have stopped the infection's spread.

Nor were the infections likely to have been caused by poor hygiene when handling contact lenses.

Results of the study, which was conducted by the CDC, are published in the Journal of the American Medical Association.

A worldwide recall of the contact lens solution was issued in May, following the discovery that users were more than 20 times as likely to develop Fusarium keratitis, an infection of the cornea, as nonusers.

From June 2005 through June 2006, 164 confirmed cases of the infection were reported in 33 states and a US territory. Ninety-four percent of those cases occurred among soft contact lens wearers. Thirty-four percent of the cases required corneal transplantation.

The MoistureLoc product does have two ingredients that are not found in other soft contact lens solutions, the researchers noted, which might have contributed to some of the infections. The study suggests that there might have been a complex interaction between the Fusarium fungus and contact lens cases or the lenses themselves.

Although the Fusarium outbreak apparently was not caused by contamination during production or by poor contact lens cleaning, contact lens wearers are advised to stop using Renu with MoistureLoc, to report any suspected infections to their eye doctor, to practice good eye hygiene, and to use their contact lenses and other solution products only as directed.

All remaining MoistureLoc solution should be discarded, the FDA has recommended. The agency suggests that "rubbing and rinsing" may be a better method for cleaning a contact lens than the "no rub" method.

Contact lens wearers should stick the recommended schedule for wearing and replacing their lenses. They should use soap and water to wash their hands, and then dry them prior to handling a lens. It's important to keep the contact lens case clean and replace it every three to six months.

Redness, pain, tearing, increased light sensitivity, blurry vision, discharge or swelling are symptoms that require prompt consultation with an eye doctor.