Herbal Supplementation in Glaucoma


Glaucoma is chronic ocular disease that leads to the deterioration of the optic nerve and its surrounding fibres. With this decline comes loss of visual field. The disease pathophysiology is multi-factorial, with the primary known underlying aetiologies relating to intraocular pressure and blood flow. The only pathway by which we have found successful treatment thus far is the lowering of intraocular pressure. There are many topical ophthalmic formulations for this on the market, with new medications developing regularly and more on the horizon. Some patients only require the use of a single medication, while others require multiple medicines for optimal control. When pressure control is insufficient with medication, or when issues relating to intolerance or poor compliance arise, laser and/or and surgical procedures may be employed.

Although it is reassuring to have efficacious treatments for glaucoma, patients often are looking for additional therapies. They want to know they’re doing anything and everything they can to save their sight. Patient questions often arise surrounding lifestyle modification and/or supplement use. We do know that intraocular pressure is only part of the picture, so it seems reasonable that there may be more therapy avenues to explore. Many supplements have been studied in glaucoma; while some of them have not been proven to be beneficial, others have shown a lot of promise. Supplements studied include various vitamins, coenzyme Q10, gingko biloba, forskolin, resveratrol and cannabis.1

Among the substances evaluated for their utility in the treatment of glaucoma are flavonoids, natural compounds with various phenolic structures. Flavonoids are found in vegetables, fruits, grains, roots, stems, bark, tea and wine. They have potent anti-inflammatory, anti-oxidant, anti-mutagenic and anti-carcinogenic properties, as well as the ability to modulate key cellular enzyme functions. This broad and powerful spectrum of biological activity has popularised their use in nutraceuticals and pharmaceuticals.2

Hand holding bilberries

Bilberry and French maritime pine bark are two phenolic extracts that have been studied in a wide variety of conditions, and have shown potential in the adjunct treatment of 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 in the treatment group, after two months, was a lowering of intraocular pressure (IOP) from a baseline of 25.2 mmHg to 22.2 mmHg. The untreated group only had marginal IOP fluctuations. Most treated patients’ IOP stayed at that level for three months. The investigators also measured blood flow using Doppler. They found an improvement in blood flow in the treated group’s systolic and diastolic measurements in the central retinal, ophthalmic, and posterior ciliary arteries. Again, these effects seemed to persist after three months.3 No side effects were observed, which is in remarkable contrast to traditional glaucoma medicines. Common complaints from patients using topical glaucoma medications include redness, itching, irritation, dryness and more.

The same investigators then did a follow-up study, examining the use of bilberry and Maritime pine bark extract in combination with traditional glaucoma therapy. They chose latanoprost, a prostaglandin analogue and one of the most common first-line topical glaucoma medications. They randomised subjects to three treatment groups: latanoprost, bilberry/pine bark extract or both latanoprost and bilberry/pine bark extract. Patients were followed for 24 weeks, with monthly IOP measurement and retinal blood flow evaluation. The group using bilberry and pine bark extract alone had a lowering of IOP from 38.1 to 29.0 mmHg after 16 weeks. The IOP of those patients using latanoprost dropped rapidly, from 37.7 to 27.2 mmHg within four weeks. The group using the combination of latanoprost with bilberry and pine bark extract had a baseline IOP of 38.0. Within four weeks, IOP dropped to 27.3 mmHg, then further decreased to 24.2 mmHg after six weeks. It even continued to decline past that point, out to 12 weeks. As far as central artery blood flow, the individual therapies of latanoprost or bilberry and pine bark extract alone showed comparable levels. Combination treatment yielded higher systolic velocity from the outset. It took approximately 12 weeks for the combination treatment to yield higher diastolic velocity. Ultimately, combination therapy showed better blood flow than either latanoprost or bilberry/pine bark alone. No side effects were seen in the bilberry and pine bark extract group. Mild side effects were reported in the latanoprost group, as well as the combination therapy cohort. These included blurred vision, eyelid erythema and conjunctival erythema, all of while are likely be attributable to latanoprost.4

A third study on the use of bilberry and pine bark extract was performed in patients with asymptomatic ocular hypertension. The supplement dose used was 80 mg of bilberry and 40 mg of pine bark extract. The authors employed three treatment arms: latanoprost alone, latanoprost with bilberry and pine bark extract and dorzolamide-timolol with bilberry and pine bark extract. As expected, all three groups had a statistically significant decline in their IOP from baseline over the course of the 12-week study. The latanoprost with bilberry and pine bark extract group had a slight advantage over the other two cohorts. Systolic and diastolic flow velocities increased in all treatment groups, though the latanoprost with bilberry and pine bark cohort showed the most improvement.5

These manuscripts certainly lend great promise to the efficacy of bilberry and pine bark extract in lowering intraocular pressure and improving ocular blood flow. However, these studies were short, small and were not performed in patients with diagnosed glaucoma. There is a prospective, parallel-group, double-blind, randomized placebo-controlled clinical study underway on primary open-angle glaucoma patients,6 so those results should be available eventually. Furthermore, although the three studies discussed in this article did not find any serious side effects, there has been a single case report suggesting that bilberry may potentiate bleeding risk when combined with other anticoagulants7; therefore, caution should be exercised with these patients.

These studies on bilberry and pine bark extract have demonstrated the effectiveness of the combination, as well as its paucity of side effects; therefore, it is reasonable to consider supplementation as an adjunctive therapy in glaucoma. Patients with this condition have limited therapeutic options and want to feel they are doing everything they can to control their disease and save their sight. The safety and efficacy of bilberry and pine bark extract so far is very favourable, and more research is underway.

References

1. Lisa S., G. (2018). Supplements & Glaucoma: Advising Your Patients. Reviewofophthalmology.com. Retrieved 9 February 2021, from https://www.reviewofophthalmology.com/article/supplements-and-glaucoma-advising-your-patients.

2. Panche, A. N., Diwan, A. D., & Chandra, S. R. (2016). Flavonoids: an overview. Journal of nutritional science5, e47. https://doi.org/10.1017/jns.2016.41

3. 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.

4. Steigerwalt, R. D., Jr, Belcaro, G., Morazzoni, P., Bombardelli, E., Burki, C., & Schönlau, F. (2010). Mirtogenol potentiates latanoprost in lowering intraocular pressure and improves ocular blood flow in asymptomatic subjects. Clinical ophthalmology (Auckland, N.Z.)4, 471–476. https://doi.org/10.2147/opth.s9899

5. Gizzi, C., Torino-Rodriguez, P., Belcaro, G., Hu, S., Hosoi, M., & Feragalli, B. (2017). Mirtogenol® supplementation in association with dorzolamide-timolol or latanoprost improves the retinal microcirculation in asymptomatic patients with increased ocular pressure. European review for medical and pharmacological sciences21(20), 4720–4725. 

6. Mirtogenol and Bimatoprost on IOP in Hispanics With Open-Angle Glaucoma – Full Text View – ClinicalTrials.gov. Clinicaltrials.gov. Retrieved 8 February 2021, from https://clinicaltrials.gov/ct2/show/NCT04380025.

7. Aktas, Can & Şenkal, V. & Sarikaya, Sezgin & Karti, Sami. (2011). Bilberry potentiates warfarin effect? Turk Geriatri Dergisi, 14, 79-81.

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:

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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