This year has been marked by many terrifying things, but perhaps the most surprising of the 2023 horrors was … eye drops.

The seemingly innocuous teeny squeeze bottle made for alarming headlines numerous times during our current revolution around the sun, with lengthy lists of recalls, startling factory inspections, and ghastly reports of people developing near-untreatable bacterial infections, losing their eyes and vision, and dying.

Recapping this unexpected threat to health, the Food and Drug Administration on Tuesday released an advisory titled "What You Should Know about Eye Drops" in hopes of keeping the dangers of this year from leaking into the next. Among the notable points from the regulator was this stark pronouncement: No one should ever use any homeopathic ophthalmic products, and every single such product should be pulled off the market.

The point is unexpected, given that none of the high-profile infections and recalls this year involved homeopathic products. But, it should be welcomed by any advocates of evidence-based medicine.

Homeopathy is an 18th century pseudoscience that produces bogus remedies that work no better than a placebo and, if prepared improperly, can be toxic, even deadly. The practice relies on two false principles: the  "law of similars," aka "like cures like," meaning a substance that causes a specific symptom in a healthy person can treat conditions and diseases that involve that same symptom, and the "law of infinitesimals," which states that diluting the substance renders it more potent. As such, homeopathic products begin with toxic substances that are then extremely diluted—often into oblivion—in a ritualistic procedure. Some homeopaths hold that water molecules can have "memory."

Clear risks

In the US, these products are marketed as legitimate treatments and sold alongside evidence-based treatments (though consumer advocates are trying to change that). The reason this is allowed for now is because of a regulatory quirk: Based on the 1938 Food, Drug, and Cosmetic Act, homeopathic products are generally considered exempt from pre-market FDA safety and efficacy reviews as long as the active ingredient in the product is included in the Homeopathic Pharmacopoeia, a list of substances approved by homeopaths.

In recent years, the FDA and the Federal Trade Commission have cracked down on homeopathic products, though. And it seems from today's advisory that the FDA is not holding back on homeopathic products for the eyes. The regulator notes that any products meant for the eye "pose a heightened risk of harm" because the eyes are an immune-privileged site in the body. That is, innate immune responses are restrained in the eye to prevent damaging inflammation, which could threaten vision. "Any drug used in the eyes must be sterile to reduce the risk of infection," the FDA said.

But whether or not homeopathic eye drops are labeled as sterile doesn't seem to matter to the FDA. The regulator cautions: "Do not use ophthalmic products that: Are labeled as homeopathic, as these products should not be marketed." Their lack of pre-market safety and efficacy reviews appears to be enough to warrant avoidance.

The FDA also cautions consumers not to use any over-the-counter eye drop product that claims to treat glaucoma, cataracts, retinopathy, or macular degeneration because there are simply no actual over-the-counter treatments for these conditions. If a non-prescription product claims this, you can assume it's bogus and avoid it. Consumers should also avoid anything that includes Methylsulfonylmethane (MSM), which is illegally sold in the US, and anything with silver sulfate or argentum because these can permanently change the white color of your eyes.