The survey, which covered 151 healthy contact lens users, also found that of the 21 who were using MoisturePlus at the time of the recall, 15 had not heard about the recall and continued to use the product. The report was posted on the C.D.C. Website Tuesday. The report also said that the C.D.C. had learned of at least four patients who developed symptoms of infection using the product after it was recalled.  Both the C.D.C. and the Food and Drug Administration expressed growing concern about the possibility that lack of attention among consumers and doctors to the recall was leading to unnecessary risks.  “We asked the company in a meeting last week to step up its efforts to publicize the recall,” said Kristine Mejia, a spokeswoman for the F.D.A. On Wednesday, the agency issued a notice to consumers on its Web site saying the recall is a Class I event, its most serious level of recall.  The agency said Advanced Medical, based in Santa Ana, Calif., had initially focused its recall efforts on communications with eye care professionals and retailers. The F.D.A. said Advanced Medical reported that it had distributed more than 57 million bottles worldwide, including nearly 28 million in the United States, in the two years before the recall began. How many remain in circulation is not clear.  Advanced Medical said it believed its publicity efforts had been “appropriate to ensure the effectiveness of the recall.” Advanced Medical’s call center in the United States has received nearly 100,000 calls, including more than 55,000 requests from consumers for product return and reimbursement kits, according to Steve Chesterman, a spokesman.  Mr. Chesterman said in an e-mail message that the C.D.C. findings were based on “a limited number of interviews.” He said the company was working with the C.D.C. and the F.D.A. to “further evaluate” the results of its communications efforts.  An article in Business Day on Friday about eye infections linked to the lens cleaner Complete MoisturePlus, produced by Advanced Medical Optics, misstated the manner in which the Centers for Disease Control learned that four contact lens users developed infections after the product was recalled on May 26, 2007. Those infections were reported individually to the C.D.C., not discovered as part of a survey that showed many contact lens users were unaware of the recall.  A version of this article appears in print on , on Page C3 of the New York edition with the headline: Eye Infections From Solution Continuing To Harm Users. Order Reprints| Today's Paper|Subscribe
More than a quarter of people who suffered serious infections linked to the recalled Complete MoisturePlus lens cleaner have required corneal transplants.