More than 12 million bottles of eye drops are being recalled over fears they could be contaminated.

Manufacturer Rohto issued the alert for six of its over-the-counter eye drops due to a 'lack of assurance of sterility.'

It is not clear whether any are contaminated, but the FDA has marked this a Class II recall, meaning there is a temporary, and reversible, risk to the eyes and vision if the products are used.

The eye drops were sold nationwide in 0.4 fl oz bottles with blue, red, green or black lids. One of the drops also comes in a pink bottle with a black lid. 

They were sold individually or in a pack of two and have best-before dates up to August 2028.

No illnesses or injuries linked to the recalls have been reported to date. 

The FDA has not issued advice for consumers. But in previous cases people have been advised to stop using the drops immediately and to throw them out or return them to sellers for a full refund. 

In 2023, a major eye drop recall was called after drops made in India were found to be contaminated with a deadly bacteria. Overall, 81 patients were sickened, 18 suffered permanent blindness and four died.

The recall was revealed in an Enforcement Report on the FDA's website, an official notice stating an item was being pulled from shelves. A press release has not been issued.

The eye drops in the alert were: Rohto Cooling Eye Drops ALL-IN-ONE, Max Strength, Optic Glow, Digi Eye, Dry Aid and Cool Relief. 

Each contains medications used to help ease eye redness, inflammation or other issues.

It includes 12 million cartons of eye drops. It was not clear how many bottles were in each carton.

A full list of the eye drops that have been recalled, including their lot numbers, is available on the FDA website. 

The drops were manufactured by Rohto-Mentholatum, which is based in Vietnam. They were distributed in the US by The Mentholatum Company, based in New York. 

It was not clear how the issue with the product was detected, but it could have been due to an inspection carried out by FDA officials. 

Lack of assurance of sterility suggests that the drops may be contaminated with bacteria or particles that could damage the eye. 

In the 2023 recall, the drops were contaminated with the bacteria Pseudomonas aeruginosa, which is resistant to standard antibiotics.

 It can infect the eye, leading to vision loss and, in extreme cases, it can spread to the blood and trigger the potentially fatal complication sepsis.

In April this year, more than three million eye drops made by California-based K.C. Pharmaceuticals were recalled also over a 'lack of assurance of sterility.'

These drops were sold in 0.5 fl oz bottles and were on shelves in CVS, Walgreens, Kroger, H-E-B and other stores.