Another Angle for Tackling Glaucoma
Do not overlook nutritional supplementation as a supportive strategy for increasing or improving ocular perfusion.
By Constance Okeke, MD MSCE
The multifactorial nature of glaucoma means that we are always trying to learn more about the disease and how to tackle it from multiple angles. IOP is not everything, as even patients with acceptable pressures continue to have disease progression. By the same token, some patients with ocular hypertension do not experience glaucomatous progression.
Many studies have centered on blood flow to the optic nerve, revealing that a decrease in ocular perfusion pressure is a risk factor for glaucoma.1 Blood carries nutrients and provides oxygenation to ocular tissues while a lack of proper nutrients and blood flow creates a toxic environment for ocular structures. Dying neuronal cells release glutamate, calcium, nitric oxide, and free radicals, which accumulate and set off a chain reaction of damage in the retina. Increasing or preserving ocular blood flow, therefore, may have vasoprotective effects allowing for oxygenation and the distribution of proper nutrients that serve to protect retinal ganglion cells.2,3
Compromised vascular health is well known to be a contributing factor to the pathogenesis of open angle glaucoma. I am mindful of the role of ocular blood flow, particularly for those patients with normal tension glaucoma or vascular issues such as hypertension or nocturnal hypotension. Particularly amid COVID, attention has been focused on ensuring our immune systems are healthy, which in turn has also heightened interest in diet and nutritional supplementation. Many of us have begun thinking in terms of what nutrients are beneficial to health overall and for glaucoma patients specifically.
Supportive Strategies
What can we do to increase ocular flow within vessels, decrease permeability, and improve vascular tone, separate from and in addition to IOP-lowering medications? Once I understand my patients’ blood pressure at different times of day, I may consider talking to their primary care physician about altering medication if it is getting too low at night.
For my normal tension glaucoma patients, those with more advanced disease, and patients who have progression despite well-controlled IOP, I regularly recommend nutritional interventions shown to help increase blood flow. Antioxidants are known to support the optic nerve environment, and a diet emphasizing green leafy vegetables rich in nitrates as well as citrus fruits may have beneficial effects.4,5 I might also talk to patients about lowering caffeine intake and increasing physical activity to optimize blood flow throughout the body.
Evidence-based Supplementation
I find that patients are very open to recommendations regarding nutrition and nutraceuticals. We are used to prescribing supplements for other eye diseases, like the AREDS formula for macular degeneration and omega fatty acids for dry eye. When it comes to optic nerve health, I recommend Optic Nerve Formula (ONF; ScienceBased Health) to my patients. The formula contains the antioxidants ginkgo biloba and bilberry, previously found to support blood flow, plus other nutrients including omega-3 polyunsaturated fatty acids (Table).6 In a unique and rigorous 4-week clinical crossover study of ONF among 42 patients with confirmed open angle glaucoma, the supplement was associated with statistically significant findings for 24 different endpoints related to improved ocular blood flow.7
The study found significant increases in peak systolic velocity up to 7.3% in two of the four major retrobulbar blood vessels, as well as increases in end diastolic velocity of up to 13% in all four retrobulbar blood vessels in participants taking the supplement. Additionally, the researchers found that vascular resistance was reduced in two of the four retrobulbar blood vessels after supplementation with the antioxidant formula. The authors concluded that, in agreement with previous findings, the results indicated that supplementation with certain antioxidants may increase blood supply to the orbit and within retinal capillary beds following 4 weeks of administration. They concluded that oral antioxidant supplementation may decrease vascular resistance over a longer period than investigated in previous trials. No adverse events associated with the supplement were reported during the study and no changes in IOP or blood pressure were seen.
Conclusion
Based on this research and our current understanding of the benefits of increased ocular blood flow, supplementation with ONF makes sense as a supportive treatment. This is especially true for certain classes of patients who are struggling with disease progression despite well controlled IOP and those who have additional risk factors of concern. I believe nutritional supplements as a means of improving ocular blood flow are under-discussed and underutilized.
Constance Okeke, MD, MSCE is an Assistant Professor of Ophthalmology, Eastern Virginia Medical School, Norfolk Glaucoma specialist and cataract surgeon, CVP Physicians/Virginia Eye Consultants, Norfolk
Contact: [email protected]; www.DrConstanceOkeke.com; linkedin.com/in/constance-okeke-md-msce-17277027; youtube.com/c/iGlaucoma.
Dr Okeke is an Ambassador for ScienceBased Health.
Reference
1. Leske MC. Ocular perfusion pressure and glaucoma: clinical trial and epidemiologic findings. Curr Opin Ophthalmol. 2009; 20(2):73-78. doi: 10.1097/ICU.0b013e32831eef82.
2. Harris A, Harris M, Biller J, et al. Aging affects the retrobulbar circulation differently in females and males. Arch Ophthalmol. 2000;118:1076-1080. doi: 10.1001/archopht.118.8.1076.
3. Harris A, Ciulla TA, Kagemann L, et al. Vasoprotection as neuroprotection for optic nerve. Eye. 2000;14:473-475. https://doi.org/10.1038/eye.2000.133.
4. Kang JH, Willett WC, Rosner BA, et al. Association of dietary nitrate intake with primary open-angle glaucoma: a prospective analysis from the nurses’ health study and health professionals follow-up study. JAMA Ophthalmol. 2016;134(3):294-303. doi: 10.1001/jamaophthalmol.2015.5601.
5. Kang JH, Ivey KL, Boumenna T, et al. Prospective study of flavonoid intake and risk of primary open‐angle glaucoma. Acta Ophthalmologica. 2018;96(6):e692-e700. DOI: 10.1111/aos.13705.
6. Gazzard G, Konstantakopoulou E, Garway-Heath D, et al. for the LiGHT Trial Study Group. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial. Lancet. 2019;393 (10180):1505-1516. doi: 10.1016/S0140-6736(18)32213-X.
7. Harris A, Gross J, Moore N, et al. The effects of antioxidants on ocular blood flow in patients with glaucoma. Acta Ophthalmol. 2018;96(2);e237-e241. doi: 10.1111/aos.13530.
