Are Bilberry and Pine Bark Extract Supplements Beneficial in Eye Disease?

Vaccinium myrtillus L., commonly known as bilberry, has been the object of many studies for various diseases. That’s because it is an incredibly powerful source of anthocyanins, also known as anthocyanosides. Anthocyanins are a glycosylated form of anthocyanidins. There are hundreds of different anthocyanins, only twenty of which occur naturally. These can be found in many fruits and vegetables. Their polyphenols lend the rich colour to blueberries, raspberries, strawberries and cranberries.1 Bilberry contains five anthocyanins: cyanidin, delphinidin, malvidin, peonidin, and petunidin.2

bilberries growing

Bilberry has been shown to help in a variety of ocular conditions such as glaucoma, and diabetic retinopathy. It tends to have a particular affinity for the eye and vascular tissues.3

Because of its favourable effects on blood flow, as well as its powerful antioxidant capacity, bilberry has been studied in glaucoma. One retrospective investigation reviewed the records of 332 patients with normal tension glaucoma. Some of them were treated with gingko biloba, others with bilberry, while the rest received no treatment. The mean follow-up duration was approximately two years. In the bilberry group, an improvement was found in best-corrected visual acuity and visual field mean deviation. The gingko biloba group also showed an improvement in visual field.3 This shows promise in the benefit of anthocyanins in glaucoma, especially in such a challenging cohort as those with normal intraocular pressure.

Anthocyanins have also been studied in diabetic retinopathy because they are known to address a hallmark feature of the disease – vascular permeability. Anthocyanins have been shown to stabilize the cell membrane phospholipids by inhibiting peroxidation. They also stimulate the synthesis of glycosaminoglycans in connective tissue. In addition, there is evidence that they reduce in platelet aggregation and increase erythrocyte flexibility, aiding in the prevention of haemorrhaging.4 By decreasing vascular permeability, anthocyanins have been found to be useful in retinopathies of hypertensive or diabetic origin.

Bilberry has been studied in asthenopia as well. One double-blind, randomised, parallel-group, and placebo-controlled trial examined the use of bilberry in combination with lutein and fish oil. The daily treatment capsules contained 783 mg of docosahexaenoic acid, 162 mg eicosapentaenoic acid, 59 mg of anthocyanidin from bilberry extract and 17.5 mg of lutein. A questionnaire was administered to subjects at baseline, and again after four weeks, to assess symptoms of asthenopia. What they found was that eyestrain symptoms improved in the treatment group. No side effects were observed.5

Another longer randomised, double-blind, placebo-controlled, parallel-group comparison trial looked at the use of bilberry on tonic accommodation during use of a digital device. This was intended to give an objective measurement of eye fatigue. The treatment group received 240 mg of standardised bilberry extract. The authors found a significant improvement in tonic accommodation in the bilberry group, as compared to the placebo cohort.6

An animal study has suggested that bilberry may also be useful in dry eye. The investigators performed a randomised, double-blind, placebo-controlled trial on rats with dry eye. They found an improvement in tear secretion with Schirmer’s testing in the bilberry treatment group. Human studies are needed to corroborate these findings.7

Another supplement that has shown value in ocular health is a standardised bark extract of the French maritime pine, Pinus pinaster. It has powerful anti-oxidant capacity, doubling the synthesis of anti-oxidative enzymes and acting as a free radical scavenger. It also plays a role in the regeneration and preservation of vitamins C and E, potentiating its anti-oxidant activity. It is a powerful vasodilator and an antagonist to inflammation.8

Bilberry and French maritime pine have been studied in combination as a potential therapeutic supplement for glaucoma. Steigerwalt et al (2008) studied a standardised combination of these two extracts in a small group of patients with asymptomatic ocular hypertension. What they found, after two months, was that the treated group’s intraocular pressure (IOP) dropped from a baseline of 25.2 mmHg to a post-treatment level of 22.2 mmHg. The untreated group only had marginal IOP fluctuations. The IOP lowering seemed to persist for at least three months. The investigators also measured retinal blood flow using Doppler. They found an improvement in the treated group’s systolic and diastolic velocities. These effects also persisted at the three-month mark. No side effects were observed.9 This absence of side effects is in stark contrast to treatment with traditional topical glaucoma medicines, which can cause redness, itching, irritation, dryness and more. Although the patients in this study did not have diagnosed glaucoma, the fact that there was an improvement in intraocular pressure and blood flow with supplementation is very promising. These are precisely the aetiologies that we attempt to target in the treatment of glaucoma.

Pine bark extract has been found to increase vascular resistance, specifically in the capillaries10, and therefore has been studied in diabetic retinopathy. A study of 24 patients with diabetic retinopathy was done using treatment with pine bark extract for three months. Investigators enrolled patients with early stages of retinopathy, characterised by mild to moderate retinal oedema. The treatment group showed statistically significant improvement in retinal oedema score and retinal thickness, as compared to the placebo group, which showed no substantial change. Central retinal artery laser Doppler flow velocity also showed a statistically significant improvement relative to the control group. This is a very positive indication of the therapeutic potential for pine bark extract, especially given this group of patients already had established disease with vision-threatening potential at baseline.11

Bilberry and pine bark extracts are two powerful compounds that have shown to be beneficial in the pathophysiology of various ocular diseases. The anti-oxidant and anti-inflammatory properties of these two substances, in addition to their other mechanisms of action, render them potent adjunct therapies in conditions such as glaucoma and diabetic retinopathy, among others.


1. Benzie, I., & Wachtel-Galor, S. (Eds.). (2011). Herbal Medicine: Biomolecular and Clinical Aspects. (2nd ed.). CRC Press/Taylor & Francis.

2. Gizzi, C., Belcaro, G., Gizzi, G., Feragalli, B., Dugall, M., Luzzi, R., & Cornelli, U. (2016). Bilberry extracts are not created equal: the role of non anthocyanin fraction. Discovering the “dark side of the force” in a preliminary study. European review for medical and pharmacological sciences20(11), 2418–2424.

3. Shim, S. H., Kim, J. M., Choi, C. Y., Kim, C. Y., & Park, K. H. (2012). Ginkgo biloba extract and bilberry anthocyanins improve visual function in patients with normal tension glaucoma. Journal of medicinal food15(9), 818–823.

4. Perossini, M., Guidi, G., Chiellini, S., & Siravo, D. (1987). Diabetic and hypertensive retinopathy therapy with Vaccinium myrtillus anthocianosides (Tegens) double blind placebo-controlled clinical trial. Ann Ottalmol Clin OculCXIII(12), 57-102. Retrieved 9 February 2021.

5. Kawabata, F., & Tsuji, T. (2011). Effects of dietary supplementation with a combination of fish oil, bilberry extract, and lutein on subjective symptoms of asthenopia in humans. Biomedical research (Tokyo, Japan)32(6), 387–393.

6. Kosehira, M., Machida, N., & Kitaichi, N. (2020). A 12-Week-Long Intake of Bilberry Extract (Vaccinium myrtillus L.) Improved Objective Findings of Ciliary Muscle Contraction of the Eye: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Comparison Trial. Nutrients12(3), 600.

7. Riva, A., Togni, S., Franceschi, F., Kawada, S., Inaba, Y., Eggenhoffner, R., & Giacomelli, L. (2017). The effect of a natural, standardized bilberry extract (Mirtoselect®) in dry eye: a randomized, double blinded, placebo-controlled trial. European review for medical and pharmacological sciences21(10), 2518–2525.

8. Rohdewald P. (2002). A review of the French maritime pine bark extract (Pycnogenol), a herbal medication with a diverse clinical pharmacology. International Journal of Clinical Pharmacology and Therapeutics, 40(4):158-168.

9. Steigerwalt, R. D., Gianni, B., Paolo, M., Bombardelli, E., Burki, C., & Schönlau, F. (2008). Effects of Mirtogenol on ocular blood flow and intraocular hypertension in asymptomatic subjects. Molecular vision14, 1288–1292.

10. Schönlau, F., & Rohdewald, P. (2001). Pycnogenol for diabetic retinopathy. A review. International ophthalmology24(3), 161–171.

11. Steigerwalt, R., Belcaro, G., Cesarone, M. R., Di Renzo, A., Grossi, M. G., Ricci, A., Dugall, M., Cacchio, M., & Schönlau, F. (2009). Pycnogenol improves microcirculation, retinal edema, and visual acuity in early diabetic retinopathy. Journal of ocular pharmacology and therapeutics: the official journal of the Association for Ocular Pharmacology and Therapeutics25(6), 537–540.

The author of this article takes full responsibility for the accuracy of this article and is not in any way affiliated or employed by Intelligent Formula – any views stated is entirely the author’s view.

About the Author:

Sara N. Frye, OD, MPH, FAAO

Dr. Sara Frye (née Gaib) obtained her Bachelor of Science from the University of British Columbia in Canada, after growing up in France. Her Doctor of Optometry (OD) degree is from Nova Southeastern University, where she received the Florida Optometric Association Presidential Award upon graduation in 2009. She went on to complete a post-doctoral residency at the University of California, Berkeley. She has a demonstrated passion for lifelong learning, going on to do her Master of Public Health (MPH) at the University of Arizona. She is also a Fellow of the American Academy of Optometry (FAAO).

Following residency, Dr. Frye was on faculty at Midwestern University for five years. She earned the rank of Associate Professor for her performance in teaching, research and service. Although her residency training was in the area of cornea & contact lenses, her current practice focuses on the diagnosis and treatment of ocular disease. She also does freelance medical writing in the realm of eye care.

Dr. Frye is passionate about travel, cooking, nutrition, health and fitness.

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bottle of Vision Defender BP

Vision Defender BP contains natural extracts of bilberry and pine bark in a convenient vegan-friendly capsule.