Eye diseases: Prevention with Herbs

Dr. James Manos (MD)
July 5, 2019

Herbs & dietary supplements that have been studied for eye diseases

Herbs & dietary supplements that have been studied for eye diseases

(with green color are the herbs & dietary supplements that the author of this text personally considers more important for this issue)

Ocular (related to the eye) problems:

·         Aloe Vera

·         An in vitro study concluded that Aloe vera contains multiple pharmacologically active substances which are capable of modulating cellular phenotypes and functions – Aloe vera ethanol and ethyl acetate extracts may be used in eye drops to treat inflammations and other ailments of external parts of the eye such as the cornea]

·         Anthocyanins

·         beta-carotene

·         Bilberry

·         Eyebright

·         Euphrasia officinalis L. (Eyebright) is an herb traditionally used in folk medicine, mainly in the treatment of eye disorders. An in vitro study analyzed the activity of three extracts of E. officinalis L. (ethanol, ethyl acetate, and heptane) on cultured human corneal epithelial cells (10.014 pRSV-T) (cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber). In conclusion, the authors show that the likely effects of the application of Euphrasia officinalis (Eyebright) preparations as a supplementary therapy for eye disorders are associated with ethanol and ethyl acetate extracts, not the heptane extract.

·         Glaucoma [(usually manifested as increased IOP (intraocular pressure). However, this may not occur in normal-tension glaucoma); see also ΄΄Normal tension glaucoma (NTG)΄΄]:

·         Citicoline (CDP – Choline; INN)

·         A human study on glaucoma patients with moderate visual defects showed improvement in retinal function (objectively evaluated by pattern electroretinogram recordings) and of neural conduction along visual pathways (assessed objectively by visually evoked potential recordings) in glaucoma patients after two 60-day periods of oral or intramuscular treatment with citicoline; however, partial regression of this improvement was detected after two 120-day periods of a washout – this suggests that the beneficial effects observed are in part treatment-dependent; the extension of citicoline treatment up to a period of 8 years lead to the stabilization or improvement of the glaucomatous visual dysfunction; the results of this study suggest potential neuroprotective effects of citicoline in the glaucomatous disease.

·         Kudzu

·         alpha-lipoic acid

·         Goji berry (wolfberry)

·         The active component of Wolfberry (Lycium barbarum; goji berry), Lycium barbarum polysaccharides (LBP), has been shown to be neuroprotective to retinal ganglion cells (RGCs) against ocular hypertension (OH) (increased IOP (intraocular pressure) is a significant risk factor for glaucoma). Aiming to investigate whether this neuroprotection is mediated via modulating immune cells in the retina, a study used multiphoton confocal microscopy to examine morphological changes of microglia in whole-mounted retinas (microglia are a type of glial cells that are the resident macrophages of the central nervous system and thus act as the first and primary form of active immune defense there). The results implied that the neuroprotective effects of Lycium barbarum polysaccharides (LBP) were partly due to modulating the activation of microglia.

·         Mirtogenol (R)

·         Mirtogenol (TM) is a patented product with standardized bilberry extract & Pycnogenol (R) (dried French maritime pine bark extract); a human study concluded that Mirtogenol lowered elevated intraocular pressure (IOP) in patients almost as effectively as latanoprost. However, it takes much longer (24 vs. 4 weeks); the combination was more effective for lowering IOP and yielded better retinal blood flow.

·         Another human study concluded that improved ocular blood flow may contribute to the prevention of glaucoma; the results of this study indicate that Mirtogenol may represent a safe preventative intervention for lowering the risk of developing symptomatic glaucoma by controlling intraocular pressure (IOP) and improving ocular blood flow.

·         Astaxanthin

·         A study that investigated the protective effect of astaxanthin (ASX) on the retina in rats with elevated intraocular pressure (EIOP) showed that latencies of all visual evoked potentials (VEP) components were significantly prolonged in EIOP and returned to control levels following ASX administration; also when compared to controls, EIOP significantly increased retinal protein oxidation which returned to baseline levels in ASX treated EIOP group; moreover, NOS-2 expression determined by Western blot analysis and immunohistochemical staining was more significant in rats with EIOP compared to ASX and control groups – in conclusion, the presented data of the study confirmed the role of oxidative injury in elevated intraocular pressure (EIOP). They highlighted the protective effect of astaxanthin (ASX) in ocular (related to the eye) hypertension.

·         Ginkgo biloba

·         One small study found that people with glaucoma who took 120 mg of ginkgo daily for 8 weeks had improvements in their vision.

·         Normal-tension glaucoma (NTG):

·         Ginkgo biloba extract (GBE) and anthocyanins (e.g., from bilberry)

·         The results of a human study suggest that (bilberry) anthocyanins and GBE may be helpful in improving visual function in some individuals with normal-tension glaucoma (NTG).

·         Taking ginkgo leaf extract by mouth seems to improve pre-existing damage to the visual field in people with normal-tension glaucoma.

·         One small study found that people with glaucoma who took 120 mg of ginkgo daily for 8 weeks had improvements in their vision.

Optic neuropathy (of the eye; see also ΄΄Leber’s hereditary optic neuropathy΄΄):

·         Citicoline (CDP – Choline; INN).

·         The results of a human study suggest a beneficial effect of oral Citicoline in non-arteritis ischemic optic neuropathy (NION).

·         Retinopathy/ retinal disease (a disease that causes damage to the retina of the eye):

·         Bilberry, Ginkgo Biloba (the flavonoids found in ginkgo may help stop or lessen some retinal problems).

·         Ligusticum wallichii (Chuanxiong)

·         A study concluded that tetramethylpyrazine (TMP), the active ingredient of Chuan Xiong, could prevent or alleviate certain ischemic retinal degenerations without producing significant cardiovascular side effects.

·         French maritime pine bark extract – Pycnogenol

·         Taking pycnogenol daily for two months seems to slow or prevent further worsening of retinal disease caused by diabetes, atherosclerosis, or other medical conditions. It also appears to improve eyesight.

·         A study concluded that Pycnogenol taken at this early stage of retinopathy may enhance retinal blood circulation accompanied by regression of edema, which favorably improves the vision of patients.

·         Propolis

·         The findings of a study indicated that Brazilian green propolis has neuroprotective effects against retinal damage both in vitro and in vivo and that a propolis-induced inhibition of oxidative stress may be partly responsible for these neuroprotective effects.

·         Blueberry

·         In a rat model of light-induced retinopathy, histological examination of the retinal section confirmed the electroretinography results, showing protection of the outer nuclear layer of the retina in the Wistar rats fed with blueberries, while all placebo-fed rats and blueberry-fed Brown-Norway rats showed evidence of retinal damage concentrated in the superior hemiretina; the neuroprotective potential of anthocyanins in this particular model is discussed in terms of interaction with rhodopsin/phototransduction and in terms of antioxidative capacity.

·         An in vitro study showed that blueberry anthocyanin extracts (BAE) are beneficial to Retinal pigment epithelium (RPE) cells by protecting these cells against light-induced damage through the suppression of aging and apoptosis (programmed cell death) as well as the downregulation of the over-expressed vascular endothelial growth factor (VEGF) to normal level – these results demonstrate that BAE is efficacious against senescence and light-induced damage of RPE cells.

·         Retinal sensitivity on light perception augmentation:

·         Eleuthero (called wrongly by some as Siberian ΄΄ginseng΄΄)

·         Administration of a liquid Eleutherococcus extract changes light perception by increasing retinal sensitivity; this effect was more pronounced in humans with a weak type of high nervous activity in the evening hours.

·         Retinitis pigmentosa:

·         Saffron (dried stigmas of the plant Crocus sativus)

·         Myopia:

·         Bilberry

·         A human study showed that fermented bilberry extract is effective in causing increases in subjective accommodation and mesopic contrast sensitivity (CS) in myopic eyes.

·         Eye surgery:

·         Hyaluronic acid

·         Hyaluronic acid is a naturally occurring polysaccharide with distinct physicochemical properties that underlie its application as a viscoelastic tool in ophthalmological (eye) surgery. In cataract surgery, the role of hyaluronic acid in facilitating procedures and protecting the corneal endothelium is well established. Some benefit has also been gained with using hyaluronic acid in penetrating keratoplasty, trabeculectomy, retinal reattachment, and trauma surgery. However, its efficacy in these indications is less well defined.

·         Eye infection:

·         Berberine [a compound found in goldenseal]

·         Berberine may help people with ocular (of the eye) trachoma infections, a disease characterized by keratoconjunctivitis.

·         Note: a study showed that goldenseal root powder increased the risk of liver tumors in rats and mice. Another study showed that the administration of goldenseal root powder resulted in increased incidences of non-neoplastic lesions in the liver of male and female rats and male mice. There is little information about the safety of high dosages or the long-term use of goldenseal.

·         Cataract treatment/ delay of the process of cataractogenesis (cataract development):

·         L-Carnosine

·         A study showed the ability of carnosine to restore most of the lens transparency in organ-cultured rat lenses exposed to similar denaturing conditions used for the in vitro experiment.

·         N-acetylcarnosine (NAC)

·         A study demonstrated that after 6 months, 90% of NAC-treated eyes showed improvement in best-corrected visual acuity (7 to 100%), and 88.9% showed a 27 to 100% improvement in glare sensitivity – the study concluded that topical NAC shows potential for the treatment and prevention of cataract.

·         Another study showed that lens opacification was improved with treatment in eyes with immature cataract or nuclear sclerosis. In eyes with mature cataract or cataract with associated intraocular inflammatory pathology, less reduction was seen.

·         A study concluded that N-acetylcarnosine is useful in the management of age-related cataract reversal and prevention.

·         Holy basil (Tulsi)

·         A study on rats and rabbits concluded that Ocimum sanctum delayed the process of cataractogenesis (cataract development) in both models. The higher doses are more effective and do not have a promising protective role rather than a curative one. The effects are more evident in galactosemic cataract.

·         Cataract prevention :

·         Bilberry

·         A study in rats concluded that the OXYS rat strain is a useful model for macular degeneration and senile cataract. Long-term supplementation with bilberry extract (BE) prevents macular degeneration and cataract.

·         Holy basil (Tulsi)

·         Alpha-lipoic acid

·         Lutein and zeaxanthin

·         A study concluded that higher dietary intakes of lutein & zeaxanthin, and vitamin E from food and supplements significantly reduced the risk of cataract.

·         Lycopene

·         A study concluded that natural antioxidants, such as lycopene derived from tomato, have a similar effect as butylated hydroxytoluene (BHT) in delaying cataractogenesis (cataract development) in rats.

·         Another study concluded that lycopene protects against experimental cataract development through its antioxidant properties, and it may be useful for prophylaxis or therapy against cataract.

·         Propolis & Vitamin C & quercetin

·         The results of a study showed that propolis, diclofenac, vitamin C, and quercetin prevented cataract formation to the extent of 70, 60, 58.4, and 40%, respectively. The antioxidant treatment caused significant changes in enzyme activities and MDA levels.

·         Acetylcarnitine (acetyl – L – carnitine, ALC, or ALCAR)

·         An animal study concluded that ALCAR prevents selenite-induced cataractogenesis in Wistar rat pups, possibly by inhibiting the depletion of antioxidant enzyme and redox system components and inhibiting lipid peroxidation.

·         Chlorella

·         The results of a study on rats indicate that Chlorella has antioxidant activity and may be beneficial for preventing diabetic complications such as cataract.

·         Astaxanthin

·         A study demonstrated that selenite, but not selenate, would interact with the carotenoid astaxanthin (ASTX), as determined using isothermal titration calorimetry and NMR. Such interactions between ASTX and selenite were also supported by the attenuation of selenite-induced turbidity by ASTX (0-12.5 microM) in vitro. In vivo experiments also showed that ASTX attenuated rats' selenite-induced cataractogenesis (cataract development).

·         Kale

·         Leafy green vegetables, like kale, are high in lutein and zeaxanthin, two nutrients found in the healthy eye that are believed to lower the risk for age-related macular degeneration (AMD) and cataract. One large study showed that women with diets high in lutein were 23% less likely to develop cataract than those with low diets.

·         Glutathione

·         Cataract formation is one of many damaging changes that can occur from an overproduction of oxidants, possibly in combination with deficiencies of an important protective antioxidant called glutathione. Glutathione at elevated levels in the eye helps fight against free radicals. One theory is that in the aging eye, barriers prevent glutathione and other protective antioxidants from reaching the nucleus in the lens, thus making it vulnerable to oxidation.

·         Age-related macular degeneration (AMD or ARMD; an eye disease that occurs when the macula, the part of the retina responsible for central vision, starts to deteriorate.// Macular degeneration, often called age-related macular degeneration or AMD, is an eye disease that affects the retina, the back part of the eye.  The number one cause of blindness in the US, AMD is a degenerative eye disease that gets worse as time goes on): 

·         Anthocyanidins

·         beta-carotene

·         Bilberry

·         A study in rats concluded that the OXYS rat strain is a useful model for macular degeneration and senile cataract. Long-term supplementation with bilberry extract (BE) prevents macular degeneration and cataract.

·         Ginkgo Biloba

·         Ginkgo biloba extract contains two constituents (flavonoids and terpenoids) that have antioxidant properties, and it is believed these may help slow the progression of AMD.

·         The flavonoids found in ginkgo may help stop or reduce some problems with the retina. Some studies suggest that ginkgo may help preserve vision in those with AMD.

·         There is some early evidence that ginkgo leaf extract might improve symptoms and distance vision in people with AMD.

·         A study that investigated the therapeutic efficacy of Ginkgo special extract Egb 761 on 99 patients with impaired vision due to senile, dry macular degeneration demonstrated marked improvement of the study participants' vision in both treatment groups after four weeks, with more pronounced improvements in group I (acuity increases by 0.13 in group I vs. 0.10 in group II after 24 weeks); the results demonstrate the therapeutic efficacy of Ginkgo special extract Egb 761 in patients with senile, dry macular degeneration, with obvious benefits in every-day life.

·         The AREDS 1 formula: vitamin C, vitamin E, beta-carotene, zinc, and copper

·         The National Eye Institute’s Age-Related Eye Disease Study (AREDS) found that taking a specific high-dose formula of antioxidants and zinc (the daily dose is: 500 milligrams of vitamin C, 400 International Units of vitamin E, 15 milligrams of beta-carotene, 80 milligrams of zinc as zinc oxide and two milligrams of copper as cupric oxide) may delay or prevent intermediate age-related macular degeneration from progressing to the advanced stage.

·         Lutein and zeaxanthin

·         Lutein may prevent and decrease the risk of AMD.

·         A study concluded that restoring the anti-oxidative capabilities of the retina by increasing the intake of lutein and zeaxanthin reduces the likelihood of age-related macular degeneration (AMD) and cataract.

·         A study concluded that increasing the consumption of foods rich in specific carotenoids may decrease the risk of developing advanced or exudative age-related macular degeneration - among the specific carotenoids, lutein, and zeaxanthin were most strongly associated with a reduced risk for AMD.

·         One study found that people with AMD who took lutein alone or in combination with other antioxidants had less vision loss, while those who received a placebo had no change. The National Eye Institute (NEI) has begun AREDS-2 trials focused on the addition of lutein, zeaxanthin, and omega-3 fatty acids to the original AREDS formula. The findings of the Lutein Antioxidant Supplementation Trial (LAST) support a possible therapeutic role of lutein in age-related macular degeneration (AMD).

·          Lycopene

·         Melatonin

·         A study concluded that melatonin protects the retina and delays macular degeneration).

·         Omega – 3 fatty acids/ fish oil

·         A questionnaire given to more than 3,000 people over the age of forty-nine found that those who ate more fish were less likely to have macular degeneration than those who ate less fish.

·         Also, a clinical study comparing 350 people with macular degeneration to five hundred without eye disease found that those with a healthy dietary balance of omega-3 and omega-6 fatty acids and more fish in their diets were less likely to have macular degeneration.

·         About macular degeneration, although studies suggest that eating fish (which includes the omega-3 fatty acids EPA and DHA) may reduce the risk of macular degeneration, a recent study including 2 large groups of men and women found that diets rich in LNA (alpha-linolenic acid) may increase the risk of this disease.

·         Saffron (dried stigmas of the plant Crocus sativus)

·         A study indicated that short-term Saffron supplementation improves retinal flicker sensitivity in early age-related macular degeneration).

·         Goji berry (wolfberry) [It contains beta-carotene and the carotenoids lutein and zeaxanthin)

·         A human supplementation trial showed that zeaxanthin in whole wolfberries (goji berry) is bioavailable and that a modest daily amount markedly increases fasting plasma zeaxanthin levels. These new data will support further study of dietary strategies to maintain macular pigment density.

·         A human study showed that homogenization of wolfberry in hot skimmed milk results in a formulation that has a 3-fold enhanced bioavailability of zeaxanthin compared with both the ΄΄classical΄΄ hot water and warm skimmed milk treatment of the berries.

·         A study on healthy elderly subjects concluded that daily dietary supplementation with goji berry for 90 days increases plasma zeaxanthin and antioxidant levels and protects from hypopigmentation and soft drusen accumulation in the macula of elderly subjects. However, the mechanism of action is unclear, given the lack of relationship between the change in plasma zeaxanthin and macular characteristics.

·         Zinc

·         According to the AREDS study (see above), zinc can be part of an effective treatment for age-related macular degeneration. In the same study, people at high risk of the disease who took dietary supplements containing only zinc also had a lower chance of getting advanced AMD than those who did not take dietary zinc supplements.

·         A human study showed that both zinc and antioxidants (vitamin C, vitamin E, and beta-carotene) plus zinc significantly reduced the odds of developing advanced AMD in this higher-risk group – the only statistically significant reduction in rates of at least moderate visual acuity loss occurred in persons assigned to receive antioxidants plus zinc.

·         Folic acid

·         Vitamin B

·         Grapeseed (Vitis vinifera)

·         Dark leafy greens

·         Astaxanthin

·         A human study concluded that patients treated with lutein & zeaxanthin, and astaxanthin together with other nutrients were more likely to report clinically meaningful stabilization/improvements in visual acuity (VA), contrast sensitivity (CS), and visual function through 24 months compared with non-treated subjects.

·         Kale

·         Leafy green vegetables, like kale, are high in lutein and zeaxanthin, two nutrients found in the healthy eye that are believed to lower the risk for age-related macular degeneration (AMD) and cataract.

·         Spirulina (contains beta-carotene, lutein, zeaxanthin)

·         Diabetic ocular (related to the eye) complications (such as diabetic retinopathy and microangiopathy) prevention:

·         L – Carnosine

·         A study on rats concluded that oral carnosine treatment protects retinal capillary cells in experimental diabetic retinopathy, independent of its biochemical function; the vasoprotective effect of carnosine might be mediated by the induction of protective Hsp27 in activated glial cells and normalization of hyperglycemia-induced Ang-2.

·         Garlic / aged garlic extract (AGE; also known as ‘kyolic’)

·         Ginger

·         In a study, it prevented diabetic cataract in rats, mainly through its antiglycation properties.

·         Ginkgo Biloba

·         There is some evidence that taking ginkgo leaf extract by mouth for six months can significantly improve color vision in people whose retinas have been damaged by diabetes.

·         Kudzu

·         It has been studied in the treatment of diabetic retinopathy.

·         Alpha – lipoic acid

·         A study on mice concluded that alpha-lipoic acid injection significantly inhibited cataract development and reduced blood glucose levels in rats fed the ΄΄high-energy΄΄ diet.

·         N – acetylcarnosine (NAC) & histidyl-hydrazide

·         A study concluded that the bioactivation antioxidant NAC and histidyl-hydrazide are potent agents with pleiotropic effects for ophthalmic therapy of senile (of the elderly) cataract and diabetic ocular (of the eye) complications.

·         French maritime pine bark extract – Pycnogenol

·         It has been used for diabetic retinopathy.

·         A study concluded that Pycnogenol taken at this early stage of retinopathy may enhance retinal blood circulation accompanied by regression of edema, which favorably improves the vision of patients.

·         Goji berry (wolfberry)

·         Α study in mice showed that dietary wolfberry restored the thickness of the whole retina, in particular, the inner nuclear layer and photoreceptor layer, and the integrity of the retinal pigment epithelia (RPE), and the ganglion cell number in db/db mice. The study concluded that dietary wolfberry on retinal protection in diabetic mice is partially due to zeaxanthin and/ or lutein.

·         Coenzyme Q10 

·         A study in mice showed that reactive oxygen species and reduced PLCβ3 expression may contribute to the sensory deficits in the late-stage diabetic db(-)/db(-) mouse and that early long-term administration of the antioxidant CoQ10 may represent a promising therapeutic strategy for type 2 diabetes neuropathy.

·         Curcumin/ turmeric

·         A human study concluded that preliminary observations indicate the value of curcumin when administered in a bioavailable form as with Meriva (R) (a proprietary complex of curcumin with soy phosphatidylcholine) in the management of diabetic microangiopathy and retinopathy.

·         Chlorella

·         The results of a study on rats indicate that Chlorella has antioxidant activity and may be beneficial for preventing diabetic complications such as cataract.

·         Anterior uveitis (inflammation of the uvea; the uvea consists of the middle, pigmented, vascular structures of the eye and includes the iris, ciliary body, and choroid):

·         Turmeric/ curcumin

·         It has been studied for chronic anterior uveitis; a preliminary study suggests curcumin may help treat uveitis; in one study of 32 people with chronic anterior uveitis, curcumin was effective as corticosteroids, the type of medication usually prescribed.

·         A human study on patients suffering from chronic anterior uveitis concluded that the efficacy of curcumin and recurrences following treatment are comparable to corticosteroid therapy which is presently the only available standard treatment for this disease – the lack of side effects with curcumin is its most significant advantage compared with corticosteroids.

·         A study on patients with recurrent anterior uveitis of different etiologies showed that curcumin-phosphatidylcholine complex (Meriva (R) (Norflo)) was well tolerated and could reduce eye discomfort symptoms and signs after a few weeks of treatment in more than 80% of patients.

·         Photophobia (light sensitivity of the eyes):

·         Lutein and zeaxanthin

·         Contact lenses & protection from oxidative stress:

·         Lactoferrin

·         Tear fluid contains antioxidative compounds, vitamin C, glutathione, superoxide dismutase, and lactoferrin (LF), which protect the corneal epithelium from the effects of ultraviolet irradiation, direct airflow, and chemical agents. However, these natural defenses against oxidative stress can decrease, favoring the development of anterior eye disorders, such as keratoconus, dry eye, and Sjogren syndrome. LF is an iron-binding glycoprotein in mammalian secretions such as tears and milk, endowed with different physiological functions such as antimicrobial, antiviral, and antioxidant activities. A study investigated the capability of different soft contact lenses to adsorb and release LF to restore cellular viability in oxidative stress conditions. The results demonstrate that lactoferrin (LF) – loaded contact lenses could represent a new therapeutic approach to treat ocular surface pathologies characterized by high levels of oxidative stress.

·         Neuroprotective against retinal damage:

·         Astaxanthin

·         An in vitro and an in vivo (in mice) study concluded that its findings indicated that astaxanthin had neuroprotective effects against retinal damage in vitro and in vivo. Its protective effects may have been partly mediated via its antioxidant effects.

          Thanks for reading