This blog started out as a a talk about Bilberry (Vaccinium myrtillus). Bilberry is in fact one of the very first herbs I ever used, even before I knew anything about medicine and herbalism.
The Herb and Start of my Connection to it
Now I am finding that it is impossible to discuss this amazing little plant without also sharing at least a little of my own personal journey through near-sightedness. Few people know this, but I was very near-sighted from early childhood until my mid 30s—most likely (at least I used to think) from growing up with my nose in a book most of the time.
Any new subject that caught my attention as a child always involved a bicycle trip to the library and a stack of books (always the maximum allowed checkout) bungee-corded to the back carrier. I would then furiously pedal the mile or so home on my back-heavy bike that wobbled and threatened to force a fall at any turn I didn’t take slowly enough in my haste to get home and start reading.
Almost 20 years later – after my first 4 year enlistment in the Army – I threw away my glasses and contact lenses.
I was a student living on the hill in Boulder, CO, using my GI Bill for school and rent. I didn’t have a car and spent most of my time training martial arts when I was supposed to be in class anyway, so I could get away with being vision impaired as I worked through at least an hour or two of vision exercises every day while also discovering and then taking bilberry as a daily supplement.
While the bilberry didn’t directly affect my daytime acuity, I did notice that it helped my horrible night vision at that time. I also found it seemed to energize me. I’ve never been a coffee drinker, but bilberry in the morning was my own version of something to pick me up in that way.
More details on my journey with poor vision in a second but since using it for that during my years as a clinical herbalist, I discovered so many amazing things about both the berry and the leaf, including that it is one of the few herbs that contain the type of proanthocyanidin —type A, also found in cranberry—which helps block enteric (e.g., E. coli) bacteria from adhering to the urothelium during a UTI.
In fact, both the berry and the leaf of bilberry are very useful for urinary tract infections.
The efficacy and safety cheat sheet I am posting here about this amazing herb is the same one you can find in the Materia Medica section of our phone App – in Google Play and the Apple Store – Herbal Medics (Herbal Medics Academy).
Vision Exercises
Many of our followers and students have asked me to elucidate on how I worked with my poor vision during that time, so here is a short version of it:
I spent hours every day doing different eye exercises that I learned about from both books and seminars. The most helpful eye exercises by far were the ones I learned at a seminar that taught race car drivers and pilots methods to improve their vision beyond 20/20. These specifically involved using peripheral vision, and to this day, these exercises still work wonders for me when my eyesight is overstrained from computer work or even stress.
Back to the late 80s. Two years later, when I took my Army physical to re-enter as a Special Forces Medic (18D), I had improved my vision to 20/60 in both eyes. This would fluctuate again based on stress and probably other factors, and I often look back amazed at the fact that I made it through the Special Forces Qualification Course (SFQC) as a medic, with impaired vision. I stubbornly refused vision correction during those years and I somehow managed thanks perhaps to my extremely keen sense of hearing and general intuitive awareness of the world around me back then.
However, after getting out in the mid 90s and teaching myself database programming as a career to be able to raise a family, my eyesight crashed back into that world of myopia. It wasn’t more than four months of staring at screens all day before my acuity was back around 20/300.
After a few years of this, I was able to afford LASIK surgery. The surgeon deliberately wanted to take me only to about 20/40.. This was when LASIK was still relatively new and he was concerned that in 10 or 20 years, if I needed follow up work of any kind, there would still be enough tissue to work with.
I told him if he could get me to 20/40 I would do the rest. He looked at me with a puzzled expression and I explained all the hundreds of hours of eye exercises I had done. He was very skeptical, but happy to oblige since 20/40 was what he preferred to get me to as well. He did just that, and by my second post-surgery eye exam my acuity measured 20/15 – thanks to me once again rigorously practicing those peripheral eye exercises I had learned to do so well, years earlier.
To this day (over 26 years later) my eyesight remains around 20/20, sometimes a little worse after a lot of computer work. I can again, bring it back to clear focus within minutes of doing the peripheral vision work.
What New Data has Shown Since those Days
Contrary to what the research of the day suggested — and what I thought I was working against — myopia is probably not a muscle problem.
Instead, in the overwhelming majority of cases, near-sightedness is axial myopia — the eyeball has grown too long from front to back. The cornea and lens are focusing light perfectly well; they’re just focusing it in front of a retina that has moved out of position. Roughly every 0.3 mm of excess axial length costs you about a diopter. So for me at 20/350 uncorrected this means my eyes were a couple of millimeters longer than they should have been.
The eye normally runs a closed optical feedback loop called emmetropization. The retina reads the sign of defocus across the whole visual field — not just the fovea — and signals through the retinal pigment epithelium (RPE) and choroid to the sclera, telling it to grow or stop. Chronic hyperopic defocus, especially in the periphery, is a “keep growing” signal. Dopamine released by retinal amacrine cells under bright light is a major “stop” signal. The scleral extracellular matrix is the effector: it remodels, the globe lengthens, and it does not shrink back.
That last clause is the important one. This probably means that axial elongation is structural and permanent. If this is true, likely no exercise reverses it.
How did I go from 20/350 to 20/60 doing exercises?
Because acuity and refraction are two different measurements, and I had probably been conflating them.
Refraction measures the optics of the eye. Snellen acuity (i.e. the 20/20 Snellen chart) measures what the entire visual system — optics, retina, and cortex — can resolve. Those can move independently, and the second one is trainable.
There’s a solid body of work on this under the name perceptual learning. Adults with myopia trained on structured visual tasks show visual acuity gains on the order of 0.15 to 0.22 logMAR — one and a half to two-plus lines on the chart — and contrast sensitivity improvements that in some protocols range from 10% to over 100%. The critical detail, and the reason I trust this explanation for my own case: when those studies measured refractive error, pupil size, and near point of accommodation before and after training, it’s likely that nothing optical had changed.
What changes is cortical. Blur is, from the visual system’s point of view, signal buried in noise. Training improves the cortex’s ability to extract the signal — specifically by strengthening lateral interactions between collinear orientation detectors in early visual cortex.
That reframes my whole experience, and it explains something that always puzzled me: the improvement was real, measurable, and reproducible on a chart, but I never had the sense that the world had become optically crisp. It had become legible. That is until I got LASIK. Now suddenly 80% or more of the blur was gone completely and it felt like I had gone from the feeling of physical exercise with a 100 lb. pack on to getting rid of all that weight and feeling like you can fly!
Why the peripheral exercises outperformed everything else
This is the part I would love to go into more depth on if I had time to study it, because my experience was certainly unambiguous — the peripheral work from that seminar did more in months than the other (Bates, et. al.) routines had done in a year.
In my limited research, there are probably at least three plausible reasons (and they aren’t mutually exclusive):
The periphery is less punished by blur. Peripheral retina is dominated by the magnocellular pathway — large receptive fields, low spatial frequency, high temporal sensitivity. Optical blur is a low-pass filter; it destroys high spatial frequencies first. So a defocused eye loses foveal detail dramatically while peripheral motion and form processing stay comparatively intact. Training a channel that still has good signal (peripheral) is more productive than trying to train one that doesn’t. And indeed, this is a large part of the eye exercises I am referring to that work so well for me – learning to focus the peripheral vision. It is more difficult than it sounds and it took a lot of focus and repetitive training for me just to be able to really “perceive” the peripheral vision that way and then try to move it into better focus.
Expanding the attentional field reduces crowding. A lot of functional acuity loss under blur is crowding — adjacent contours interfering with target identification. Widening the useful field of view improves fixation stability, saccadic targeting, and the efficiency with which the fovea gets put on the right thing. That’s exactly why the technique came out of aviation and motorsport training rather than optometry.
It downregulates the near triad. Peripheral awareness work is functionally the opposite of sustained near fixation. Accommodation, convergence, and pupillary constriction are yoked; deliberately opening the visual field relaxes all three. Which brings me to the next piece.
The database years, and why my vision “crashed”
Two things were possibly happening at once:
- Adult-onset progression is real and my axial length very likely did increase during those years.
- Layered on top of it was likely a large pseudomyopic component — accommodative spasm and near-work-induced transient myopia. After hours of sustained close focus the ciliary muscles don’t fully release; tonic accommodation stays elevated, and you measure as more myopic than your anatomy actually is. This I have found to be well documented, and it’s reversible.
I think this is the single best explanation for the phenomenon I still notice today, 26 years post-LASIK: after a heavy computer day my acuity drops, and a few minutes of peripheral work brings it back. Nothing structural is changing in five minutes. What’s likely changing is accommodative tone, tear film distribution, and attentional set.
So I have to concede that I probably did not reverse my myopia physically. My eyes were elongated and in spite of my exercises they stayed that way.
However what I did do — and what I’d stand behind teaching — is train the processing side of the system hard enough that it substantially outperformed its own optics, twice: once when the optics were bad, and again when they suddenly got good.
The Micronutrient Picture
Bilberry’s active fraction is a family of anthocyanins — water-soluble flavonoid pigments, about fifteen distinct ones, built on five aglycone backbones: cyanidin, delphinidin, malvidin, petunidin, and peonidin, each glycosylated with glucose, galactose, or arabinose. Cyanidin-3-O-glucoside (C3G) and the delphinidin glycosides carry most of the attention.
The reason bilberry outperforms cultivated blueberry here is anatomical rather than mystical: bilberry flesh is pigmented all the way through, while highbush blueberry pigment is concentrated in the skin. Per gram, bilberry runs several times higher in total anthocyanins. This is also why standardized extracts are specified at 25–36% anthocyanosides — the whole dried berry simply doesn’t deliver a research-level dose at any sane serving size.
The Mechanisms with Real Support
Microvascular integrity. Anthocyanins stabilize capillary endothelium, reduce vascular permeability, and support endothelial nitric oxide signaling. In animal models of diabetic retinopathy, bilberry extract prevents or delays blood–retinal barrier breakdown and blunts VEGF-driven leakage. The retina is one of the most metabolically expensive and most densely capillarized tissues in the body; anything that protects the choriocapillaris and inner retinal microvasculature is doing real work.
Antioxidant and anti-inflammatory signaling. Anthocyanin-rich bilberry extract protects retinal tissue against photooxidative damage by upregulating heme oxygenase-1 and inhibiting NF-κB.
Eye fatigue under visual display load. Several Japanese randomized trials — the population that has studied this most seriously, given their VDT-worker occupational health framework — report modest improvements in subjective eye fatigue and some accommodative measures with standardized bilberry anthocyanin at roughly 40–100 mg/day over 4–8 weeks. Modest, but replicated, and directly relevant to anyone doing what I was doing in the nineties.
Finally, after doing a lot of research, I have to say that bilberry probably does not improve night vision in people with normal vision. The systematic review is pretty unambiguous: of thirty trials, twelve were placebo-controlled, and the four most recent and most rigorous randomized trials were all negative. The pattern the reviewers noted is the one that always tells the story — the better the methodology, the more negative the result. Eleven of the twelve trials used healthy subjects with normal or better than normal vision.
And the origin story most of us were told — RAF night fighter pilots eating bilberry jam before sorties — may just be wartime disinformation, cover for the introduction of airborne radar.
So what do I make of my own experience, which was that bilberry noticeably helped my night vision?
Two things probably:
First, the same review that killed the healthy-subject claim explicitly noted that the animal data and the weaker trials may warrant further study in subjects with impaired night vision — and at 20/350 with untreated axial myopia, I was decidedly not a normal-vision subject. Uncorrected myopia degrades scotopic vision disproportionately, because pupil dilation in low light widens the blur circle and recruits more peripheral corneal aberration. Any intervention that improves retinal microcirculation or contrast processing has more room to work in that eye than in a 20/20 one.
Second: I was also doing hours of vision training daily and I had every expectation of improvement which undoubtedly made me a non-standard “test subject” in yet another very specific way from the research data.
To summarize my own use of bilberry – these days I mostly use it in occasional energy smoothies. I don’t know how it has this effect on me but it certainly still does to this day. I don’t take it for my eyes specifically, but I do use it medicinally as a clinician – the berry and the leaf (in limited and careful amounts) especially for urinary tract infections.
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