"The primary clinical application for bilberry extracts has been in the prevention and treatment of opthamological disorders including glaucoma, cataracts, diabetic retinopathy, day blindness and night vision improvement. Since capillary dysfunction and inflammation also play a role in wound healing, diabetes mellitus and inflammatory joint diseases, bilberry is also used for these conditions."
Bilberry is historically know to assist night vision and vision acuity. Current research has focused on the effects of bilberrys active constituents, primarily its anthocyanosides, in the treatment of ocular disorders, vascular disorders and diabetes mellitus.
Night Vision and Day Blindness
"Anecdotal reports of RAF pilots using bilberry to improve their night vision aroused interest that led to a series of studies in which the administration of bilberry extract to healthy subjects resulted in improved night-time visual acuity, quicker adjustment to darkness, and faster restoration of visual acuity after exposure to glare. In placebo-controlled trials, individuals taking anthocyanins demonstrated significantly better night vision than those taking placebo. In uncontrolled trials involving air-traffic controllers, pilots and automobile drivers, bilberry extract improved night vision.
Further studies involving individuals with ocular disorders confirimed the beneficial effects seen in healthy subjects. The most impressive benefit was seen in individuals with pigmentary retinitis and hemeralopia (day blindness or an inability to see as distinctly in bright as in dim light). In vitro clinical effects demonstrate that, in addition to anthocyanosides positive effects on capillaries, they also have an affinity for the pigmented epithelium of the retina, the optical or functional part of the retina. Bilberry has been shown to hasten the regeneration of rhodospin (visual purple) after injection. Rhodospin is a light-sensitive pigment found in the rods of the retina that must be quickly regenerated to maintain visual sensitivity.
Bilberrys antioxidant properties and beneficial effects on collagen structures in the eye may make a significant contribution to the prevention and treatment of glaucoma. In all ocular tissues, e.g., the cornea, sclera, lamina cribosa, trabecular meshwork, vitreous, etc., collagen provides tensile strength and integrity. Morphological changes in ocular collagen precede clinically detectable abnormalities. The reduced tensile strength and integrity of aging eye tissue may result from changes in ocular collagen that lead to elevated intraocular pressure (IOP) and/or the progression of peripheral vision loss. Loss of ocular collagen integrity would explain why in glaucoma:
- similar peripheral vision loss is found in patients with normal and elevated IOP
- cupping of the optic disc occurs even at low IOP levels
- decreased aqueous outflow occurs without an apparent anatomical reason
All these deleterious symtoms involve disruption of ground substance and collagen framework integrity. Preventing collagen matrix breakdown is therefore essential in the both prevention and treatment of glaucoma, as it is in other conditions involving collagen abnormalities, e.g., atherosclerosis, rheumatoid arthritis, and periodontal disease.
The anthocyanosides found in bilberry may offer not only significant protection against the development of glaucoma, but may also be of benefit in the treatment of chronic glaucoma due to their collagen-enhancing actions. The activity of bilberrys anthocyanosides has been shown to be stronger and longer-lasting that that of rutin, which has been demonstrated to lower IOP when used as an adjunct in patients unresponsive to miotics alone. In one study, eight patients with glaucoma who were given a single oral dose of bilberry anthocyanosides (200 mg) demonstrated improvement based on electroretinography. Anthocyanosides collagen-stabilizing effect on the trabecular meshwork, which would facilitate aqueous outflow, is a likely mechanism.
Cataracts and Retinal Degeneration
Bilberry anthocyanosides may offer significant protection against the development of retinal (macular) degeneration and cataracts, particularly diabetic retinopathy and cataracts. Studies have demonstrated that diets high in anthocyanoside flavonoids retard both the rate of retinal degeneration and the occurrence of cataracts in rats. In a human clinical study in which bilberry extract (180 mg twice daily of a 25-percent anthocyanoside extract) was given with vitamin E, cataract formation was arrested in 48 of 50 patients with senile cortical cataracts.
Bilberry anthocyanoside extracts are widely used in Europe in the prevention of diabetic retinopathy, with several clinical trials supporting this use. In one month-long double-blind study, 14 patients with diabetic and/or hypertensive retinopathy were given bilberry extract equivalent to 115 mg anthocyanosides or placebo daily. Significant improvements were observed in the ophthalmoscopic parameters of 11 subjects receiving bilberry, and 12 patients showed improvement in angiographic parameters.
The positive effects noted in this and other clinical trials are likely due to bilberry anthocyanosides ability to increase intracellular vitamin C levels, thus reducing sorbitol accumulation as well as improving capillary integrity. Sorbitol is a by-product of glucose metabolism that is normally metabolized by polyol dehydrogenase to fructose, which can be excreted from the cell. In diabetics, frequent hyperglycemia results in sorbitol accumulation that creates an osmotic gradient that draws water into the cell to maintain osmotic balance. As water comes in, the cell also releases small molecules like glutathione, vitamin C, magnesium and potassium. Since these compounds are involved in activities that protect the lens from damage, the delicate proteins in the retina are more susceptible to damage. Both vitamin C and flavonoids have been shown to be potent in vitro and in vivo inhibitors of sorbitol accumulation. In laboratory experiments, they have been shown capable of inhibiting the development of diabetic cataracts."
Source: https://bit.ly/3CUD7F5 - Association for the Advancement of Restorative Medicine
Bilberry is widely used to improve night vision and to decrease vascular permeability and capillary fragility; moreover, the berry has various other reputed health benefits, although most interest has been focused on anthocyanin-related antioxidant effects - Source: https://www.ncbi.nlm.nih.gov/books/NBK92770/
Supports vision, aids ocular pressures, improves night vision. A highly nutritive antioxidant rich herb.