A spate of eyedrop warnings and recalls has caused confusion and worry about the safety of popular products used to relieve dry and irritated eyes.

The Washington Post spoke to experts about the warnings and recalls, and what they mean for eyedrop safety. Here's what they had to say.

Why are there suddenly safety concerns about eyedrops?

This week, the Food and Drug Administration warned consumers to avoid more than two dozen eye-care products after finding bacterial contamination at manufacturing facilities. No injuries were reported. Earlier this year, federal regulators announced two voluntary recalls of unsterile preservative-free eyedrops after an outbreak of serious bacterial infections that resulted in at least 14 cases of permanent vision loss and four deaths.

The FDA says it has revved up its scrutiny due to the nature of eye-care products — that is, because they are applied directly into the eye, bypassing many of the body's natural defenses.

"We are surveilling certain types of products more than ever," FDA spokesman Jeremy Kahn said.

He said FDA surveillance has increased in recent months after having declined during the coronavirus pandemic, which may account for more regulatory actions and greater attention. "We couldn't get to a lot of manufacturing facilities to do on-the-ground inspections, and we were limited in travel," he said, adding that the inspections are now at full strength.

He said consumers should know that "the FDA has strict standards for safety, quality and manufacturing and makes every effort to keep the drug supply safe."

Gary D. Novack, clinical professor of pharmacology at the University of California at Davis — with expertise in ophthalmic product development — agreed, saying the heightened attention probably is a response to the end of pandemic restrictions and "is a combination of manufacturing issues and FDA stricter enforcement of existing laws and regulations."

People may be "a bit more attuned" to these recalls because of the contaminated eye-drop scare this year, said Christopher Starr, a spokesperson for the American Academy of Ophthalmology. But the FDA's warning is a sign that regulatory oversight is working and "we can all sleep a bit easier" knowing the agency is monitoring the manufacturing process.

How can you be sure your eyedrops are safe?

Millions of Americans use eyedrops for conditions such as dry eye, glaucoma and itchiness caused by allergies or air pollution.

Eye drops "are overwhelmingly safe," said Starr, who's also an associate professor of ophthalmology at Weill Cornell Medicine. He said people should feel confident that the eye drops they find in store are safe to use if the products haven't been mentioned in a recall.

"I encourage everybody, especially if you need eye drops for a medical condition, whether it's glaucoma or dry eye, or anything else, to continue using your eye drops," he said.

T. Mark Johnson, a retina specialist who practices in Rockville, Md., and Fredericksburg, Va., recommends that consumers stick to products made by major manufacturers.

"The vast majority of products made by major manufacturers are very, very safe," he said. "They have well-established protocols. Each lot is safety tested, and they track their lots. Consumers should feel comfortable buying and using these products."

He noted that most of the recent problems have centered around smaller producers of off-brand or "no-name" drops. "I don't think consumers should be overly alarmed," Johnson said. "I think the FDA has been paying more attention to eye products in the last six to nine months given what happened earlier in the year."

Mina Massaro-Giordano, a professor of clinical ophthalmology and the co-director of the Penn Dry Eye and Ocular Surface Center, said the FDA is being "extremely cautious." She said many of her patients have contacted her worried about the latest warnings. Her advice is to ask eye doctors to recommend a product they trust. Massaro-Giordano said she gives patients pictures of brand-name eye drops they should pick up at the store.

"The tried-and-true companies that have been around for a long time," she said. "Those are the ones you want to go with."

Is it safe to use eyedrops that have expired?

No. When buying these products, consumers should always check the expiration date and be careful when using them. "Don't keep drops that are expired," Johnson said. "Cap them after use and try not to inadvertently contaminate the cap. Be sure to use the proper technique when putting the drops in your eye - take your finger, pull down the lower eyelid, and put the drops in without touching the bottle to your skin or eyelashes."

Novack added: "All recalled eyedrops should be off the shelf. For any product, read the expiration date before you purchase, and if you have any questions, ask the pharmacist."

Phillip Yuhas, an assistant professor in the college of optometry at Ohio State University, said expiration dates matter with eye drops because the active ingredients could break down and the preservatives degrade over time.

"It's very easy to forget about expiration dates," the American Academy of Ophthalmology's Starr said. "All of the same risks of these manufacturing issues can happen in your medicine cabinet."

What are the symptoms of an eye infection?

They can include yellow, green or clear discharge from the eye, pain or discomfort, redness, the feeling that something is in your eye, sensitivity to light and blurry vision. Some of these can mimic less serious conditions, so it's best to check with your eye-care practitioner if in doubt.

If you're using eyedrops and you notice you have sudden pain, or a decrease in vision, you should contact your eye doctor, said Bryce St. Clair, an optometrist and instructor of ophthalmology at the Johns Hopkins Wilmer Eye Institute

"If you have any type of mild infection in your cornea, you will know it immediately," St. Clair said. "It's not something you're going to be guessing at."

Have there been new reports of eye infections?

No. The FDA said it has not received any reports about eye infections related to its October warnings for 26 over-the-counter eye-care products. The products carry the CVS Health, Rite Aid, Leader (Cardinal Health), Rugby (Cardinal Health) and Target Up&Up labels - as well as Velocity Pharma, which retailers have identified as the eyedrops' supplier. The FDA provided a list of the products on its website, and encouraged health-care professionals and consumers to report negative effects or quality problems.

What's the difference between the new warnings and earlier recalls?

The most serious reports were linked to "preservative free" products. Preservative-free products contain mostly saline and distilled water. Many eyedrop brands contain chemical preservatives such as benzalkonium chloride, or BAK, as well as other ingredients.

Some patients are advised to use preservative-free drops. Those with severe or poorly controlled dry-eye symptoms, or who have had surgery or other illnesses require chronic moisture and may be advised to use preservative-free products to avoid the cumulative toxic effects of BAK.

In January, federal officials first warned of an outbreak of eyedrop-related bacterial infections, including reports of vision loss, blindness and death, from products contaminated with Pseudomonas aeruginosa, a drug-resistant bacterium. EzriCare Artificial Tears, a preservative-free over-the-counter product that many infected patients reported using, was recalled by its manufacturer. Delsam Pharma's Artificial Tears was also recalled.

The outbreak is associated with at least 81 infections in 18 states, four reports of enucleation — surgical removal of an eyeball — and four deaths resulting from the original bacterial outbreak.

In March, the agency reported a second recall of eyedrops, though they were not related to the outbreak. Pharmedica's Purely Soothing 15 percent MSM Drops was recalled out of concern the product wasn't sterile. Apotex's Brimonidine Tartrate Ophthalmic Solution, 0.15 percent, was pulled "out of an abundance of caution" due to cracks in some of the bottles' caps, which could affect the product's sterility, the company said.