The U.S. Food and Drug Administration issued letters to several companies -- including major pharmacy chains -- this week, warning them against manufacturing or selling unapproved eye products.
Letters were sent to CVS and Walgreens as well as six manufacturers claiming the products are illegally marketed as being able to treat conditions including cataracts, glaucoma and pink eye.
Some of the letters also addressed quality control issues at the companies concerning the safety and sterility of the products.
Nearly three weeks ago, the FDA warned the public not to use to certain products due to fears of potential bacterial or fungal contamination.
In their letters, the FDA also said people using these unapproved eye products that claim to treat or cure certain conditions may cause delay or stoppage of treatments that are approved by the agency.
"The FDA is committed to ensuring the medicines Americans take are safe, effective and of high quality," Jill Furman, director of the office of compliance at the FDA's Center for Drug Evaluation and Research, said in a statement. "When we identify illegally marketed, unapproved drugs and lapses in drug quality that pose potential risks, the FDA works to notify the companies involved of the violations."
"We will continue to investigate potentially harmful eye products and work to ensure violative products stay off store shelves so that consumers can continue taking the medicines they need without concern," the statement continued.
The FDA told the companies they have 15 days to respond to the FDA in writing to address any steps they have taken to correct violations.
A list of the products was not listed on the FDA website, but a spokesperson told ABC News the products were named in the individual letters.
For CVS, the FDA noted CVS branded "Pink Eye Relief Drops" claim to relieve redness, burning, watery discharge and feelings of grittiness.
However, the product is unapproved and, according to the FDA, may cause harm because it contains silver sulfate as a preservative, which can cause permanent bluish-gray discoloration of the eye as well as decreased night vision.
"Upon receipt of the FDA's Warning Letter, we have stopped the sale of CVS Health Brand Pink Eye Relief Eye Drops at our stores and online," a CVS spokesperson told ABC News in a statement. "Customers who purchased this product can return it to CVS Pharmacy for a full refund. We're committed to ensuring the products we offer are safe, work as intended and satisfy customers. "
For Walgreens, the FDA cited three store brand products including "Allergy Eye Drops," "Stye Eye Drops," and "Pink Eye Drops" all of which claim to treat symptoms such as itching, redness, burnings and watery discharge. The agency had the same concern about silver sulfate.
"Out of an abundance of caution, we are pulling these products," Walgreens told ABC News in a statement. "Customers who have purchased these products can return the item to their nearest Walgreens for a full refund."
In a letter to Swiss corporation, Similasan AG, the FDA noted the company not only has 12 unapproved products but also had recorded quality control violations. This included not following procedures to prevent microbiological contamination and complete data available to ensure specifications and standards were met.
Similasan AG has not responded to ABC News' request for comment.
The FDA recommends that anyone who purchased the products listed in the warning letters to speak with a health care professional and report any adverse reactions to the MedWatch program.