Bilberry and Eyebright: What the Evidence Actually Says

Two botanicals turn up in almost every eye supplement. One is named after the organ it's supposed to help. The other is famous for a wartime story about night-flying pilots.

Both have long histories and neither has the evidence people assume. Here's what they actually are, what the research found when it looked properly, and one safety warning that matters a great deal.

Bilberry is a genuine antioxidant — it contains more anthocyanins than blueberries and has some support for circulation. The famous night vision claim, though, has repeatedly failed in properly controlled trials. Eyebright has centuries of traditional use for eye complaints and essentially no clinical evidence, and it got its reputation because the flower looks like a bloodshot eye. Neither is a reason to choose an eye supplement — and never put a homemade eyebright preparation in your eye.

Bilberry: what it is

Bilberry is Vaccinium myrtillus, sometimes called European blueberry, whinberry or huckleberry. It grows wild across northern Europe and is a close relative of the cultivated blueberry.

The practical difference is visible when you cut one open. A cultivated blueberry has pale green-white flesh; a bilberry is deep red-purple all the way through, which is why it stains everything it touches.

That colour is anthocyanin — the pigment class responsible, and bilberries contain considerably more of it than ordinary blueberries. Anthocyanins are well-characterised antioxidants, and that part of bilberry's reputation is real.

The night vision story

The version everyone has heard: during the Second World War, RAF pilots ate bilberry jam before night missions and found their vision in the dark improved.

Two things are worth saying about it.

The historical trail is thin. Unlike the well-documented carrot campaign — which really did happen, as cover for airborne radar, and which we cover in our guide to vitamin A and the eyes — there's little contemporary evidence of an organised bilberry effort. The story appears to have accumulated later, quite possibly borrowing from the carrot one. They're separate myths that have blurred together.

The science was tested properly, and it didn't hold. The story was taken seriously enough to fund real research. Several small studies in the 1960s and 70s reported improvements in dark adaptation, which is where the claim's credibility came from.

Then better-designed trials followed — placebo-controlled, including military-funded work specifically interested in whether this could help personnel operating at night. They consistently found no effect on night vision or dark adaptation in people with normal eyesight. A placebo-controlled crossover study published in 2000 found no difference in night visual acuity or contrast sensitivity after bilberry supplementation.

Reviews since have reached the same conclusion: the early positive results don't survive proper controls.

What bilberry may actually do

Dismissing one claim doesn't mean dismissing the plant. There are areas with modest support.

• Antioxidant activity — well established in laboratory work. Anthocyanins are genuinely active compounds.
• Microcirculation and capillary integrity — the best-supported traditional use, and bilberry extract has been used in parts of Europe for venous insufficiency and capillary fragility.
• Eye fatigue from screen use — a few small trials have reported modest improvements in asthenopia scores. Small studies, modest effects, suggestive rather than settled.
• Diabetic retinopathy — some preliminary research into retinal microvascular effects, early and not a basis for any claim.

Fair summary: a reasonable antioxidant with some circulatory support and a plausible but unproven role in screen-related eye fatigue. Not a night vision aid.

Bilberry dosing and safety

Extracts are usually standardised to around 25% anthocyanosides, and European clinical use has typically involved somewhere in the region of 80–160 mg of standardised extract twice daily. Unstandardised powders vary enormously, so the standardisation figure matters more than the milligram number.

It's well tolerated, with occasional mild digestive upset. Two cautions worth knowing:

• Blood thinning. Anthocyanins may have a mild antiplatelet effect. If you take warfarin, clopidogrel, aspirin or any anticoagulant, raise it with your doctor, and stop before planned surgery.
• Blood sugar. Bilberry may lower blood glucose, which matters if you take insulin or oral diabetes medication.

Eyebright: what it is

Eyebright is Euphrasia officinalis, a small meadow wildflower — white petals with fine purple veining and a yellow throat. It's hemiparasitic, drawing some of its nutrition from the roots of neighbouring grasses.

Its reputation has an unusually clear origin, and it isn't a flattering one.

The Doctrine of Signatures

Medieval and Renaissance herbalism worked partly on a principle called the Doctrine of Signatures: the belief that a plant's appearance revealed what it was meant to treat. Walnuts resembled brains and were thought to aid the mind. Lungwort's spotted leaves suggested the lungs. Liverwort's lobes suggested the liver.

Eyebright's flower, with its purple veining and yellow centre, was taken to resemble a bloodshot eye. So it was used for the eyes — and has been, in European herbal tradition, since at least the fourteenth century.

That's genuinely where the association comes from. It isn't the result of anyone observing an effect; it's the result of a resemblance.

Worth being fair here: traditional use isn't worthless, and plenty of modern medicines began in folk remedies. But when the origin is visual resemblance rather than observed benefit, the prior should be set accordingly.

What the evidence says about eyebright

Very little, and that's the honest answer.

Eyebright has been used traditionally for conjunctivitis, eye irritation, inflamed lids and hay fever symptoms, usually as an infusion applied as a compress or taken as a tea. It contains iridoid glycosides, tannins and flavonoids, and tannins do have astringent properties, which may explain the sensation of relief some people report.

Rigorous clinical evidence is essentially absent. The most-cited study is a small open-label trial of eyebright eye drops in conjunctivitis published in 2000 — uncontrolled, no placebo group, and not the kind of study that establishes an effect. There's no meaningful body of controlled research behind it.

European regulators that list it generally do so on the basis of traditional use rather than demonstrated efficacy, which is a different and much lower bar.

Never make a homemade eyewash

This is the most important paragraph on the page, and it applies regardless of what you think of the herb.

Do not make an eyebright infusion, tea or compress and put it in or on your eye.

Anything applied to the eye surface needs to be sterile. A home-brewed plant infusion is not — it's warm, nutrient-rich liquid, which is close to ideal conditions for bacterial growth.

The specific danger is microbial keratitis, infection of the cornea. Pseudomonas aeruginosa is a common culprit, thrives in water, and can cause corneal ulceration and permanent vision loss within days. Contact lens wearers are at particularly high risk.

If you have a red, irritated or discharging eye, see a pharmacist or doctor. Sterile commercial preparations exist, and for anything beyond mild irritation, proper treatment is what's needed. Home remedies applied directly to the eye are a genuinely bad idea.

Taken by mouth

Oral eyebright, as found in supplement blends, is a different proposition from putting it in your eye and is generally regarded as low-risk at the small amounts used.

There's little safety data at higher doses, and it's not recommended in pregnancy or breastfeeding for want of information rather than because of known harm.

So why are they in eye supplements?

A fair question, and the answer isn't sinister.

Both have long histories in eye-related traditional use, both are inexpensive and well tolerated, and both carry strong name recognition — "eyebright" in particular does a lot of work on an ingredient list.

That's not a reason to avoid products containing them. It is a reason not to choose a product because of them. The ingredients with meaningful eye-specific evidence are lutein and zeaxanthin, covered in our guide to macular pigment, and the vitamins and minerals tested in the AREDS trials, covered in our guide to reading an eye vitamin label.

Both are in our formula — and here's the problem with that

Bellawell's Vision Care contains bilberry extract and eyebright within its 481 mg proprietary blend, and we'd rather point out something awkward than hope you miss it.

Ingredients in a proprietary blend are listed in descending order by weight. In ours, the order runs: lutein, bilberry, alpha-lipoic acid, eyebright, then zeaxanthin.

Which means eyebright — a herb with essentially no clinical evidence — outweighs zeaxanthin, one of the two carotenoids the entire category rests on. We've raised that with the manufacturer, and we think it's the wrong way round.

Bilberry's position at second is more defensible; it's a real antioxidant, and the screen-fatigue research, thin as it is, points somewhere. But we won't tell you it improves night vision, because the trials say otherwise — and that claim should come off our product page too.

The bottom line

Bilberry is a legitimate anthocyanin-rich antioxidant with some support for circulation and a plausible role in screen-related eye fatigue. Its famous night vision benefit failed every properly controlled test it was given.

Eyebright earned its name and its reputation from a resemblance rather than a result, and the clinical evidence behind it is close to nonexistent. Taken by mouth in a blend it's harmless. Brewed at home and put in your eye, it's dangerous — so don't.

When comparing eye supplements, look at the lutein and zeaxanthin figures. The botanicals are decoration.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease. This article is for general information and is not a substitute for medical or optometric advice. Never apply homemade herbal preparations to the eye — non-sterile liquids can cause serious, sight-threatening infection. Consult your doctor before taking bilberry if you take anticoagulant, antiplatelet or diabetes medication, or before any planned surgery. Eyebright is not recommended during pregnancy or breastfeeding. See a doctor or optometrist for a red, painful or discharging eye, and seek urgent care for sudden vision loss, new floaters or flashes of light, or eye pain with halos. Keep out of reach of children.