Natural therapies for ocular disorders, Part two: Cataracts and glaucoma
Pathophysiological mechanisms of cataract formation include deficient glutathione levels contributing to a faulty antioxidant defense system within the lens of the eye. Nutrients to increase glutathione levels and activity include lipoic acid, vitamins E and C, and selenium. Cataract patients also tend to be deficient in vitamin A and the carotenes, lutein and zeaxanthin. The B vitamin riboflavin appears to play an essential role as a precursor to flavin adenine dinucleotide (FAD), a co-factor for glutathione reductase activity. Other nutrients and botanicals, which may benefit cataract patients or help prevent cataracts, include pantethine, folic acid, melatonin, and bilberry. Diabetic cataracts are caused by an elevation of polyols within the lens of the eye catalyzed by the enzyme aldose reductase. Flavonoids, particularly quercetin and its derivatives, are potent inhibitors of aldose reductase. Glaucoma is characterized by increased intraocular pressure (IOP) in some but not all cases. Some patients with glaucoma have normal IOP but poor circulation, resulting in damage to the optic nerve. Faulty glycosaminoglycan (GAG) synthesis or breakdown in the trabecular meshwork associated with aqueous outflow has also been implicated. Similar to patients with cataracts, those with glaucoma typically have compromised antioxidant defense systems as well. Nutrients that can impact GAGs such as vitamin C and glucosamine sulfate may hold promise for glaucoma treatment. Vitamin C in high doses has been found to lower IOP via its osmotic effect. Other nutrients holding some potential benefit for glaucoma include lipoic acid, vitamin B12, magnesium, and melatonin. Botanicals may offer some therapeutic potential. Ginkgo biloba increases circulation to the optic nerve; forskolin (an extract from Coleus forskohlii) has been used successfully as a topical agent to lower IOP; and intramuscular injections of Salvia miltiorrhiza have shown benefit in improving visual acuity and peripheral vision in people with glaucoma.
Available from: Varun Gupta
- "Elimination of causes of cataract which were described above may reverse the cataractous changes in the initial stage. Nutritional supplements and balancing antioxidants during old age and malnutrition and in condition of diarrhea are reported in preventing senile cataract. Correction of transient metabolic defects e.g., treatment of galactosemia, copper metabolism etc., are also found useful in the prevention of cataract. "
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ABSTRACT: Natural eye lens is a crystalline substance to produce a clear passage for light. Cataract is opacity within the clear lens of the eye and is the dominant cause of socio-medical problem i.e., blindness worldwide. The only available treatment of cataract is surgery. However, insufficient surgical facilities in poor and developing countries and post-operative complications inspire researchers to find out other modes of treatment for cataract. In this review, an attempt has been made to appraise various etiological factors of cataract to make their perception clear to build up counterpart treatment. Present study is an assortment of various available literatures and electronic information in view of cataract etiopathogenesis. Various risk factors have been identified in development of cataracts. They can be classified in to genetic factors, ageing (systemic diseases, nutritional and trace metals deficiencies, smoking, oxidative stress etc.), traumatic, complicated (inflammatory and degenerative diseases of eye), metabolic (diabetes, galactosemia etc.), toxic substances including drugs abuses, alcohol etc., radiation (ultraviolet, electromagnetic waves etc.) are implicated as significant risk factors in the development of cataract.
Available from: Creina Stockley
- "In another trial, 50 patients with senile cataracts were given a combination of bilberry extract, standardized to contain 25% anthocyanins (180 mg twice daily) and vitamin E (100 mg twice daily) administered for 4 mo. The progression of cataracts was halted in 96% of the subjects treated, as compared to 76% in the control group (Head 2001). Similar to that observed in animal studies, in 30 glaucoma subjects retinal blood flow was observed to be significantly increased following administration of 50 mg anthocyanins per day for 6 mo (Table 6; Ohguro and others 2007). "
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ABSTRACT: Anthocyanins belong to the flavonoid group of polyphenolic compounds, which are responsible for the red and blue colors of plant organs such as fruits, flowers, and leaves. Due to their frequent presence in plants, particularly berry fruits, vegetables, and grapes, they are key components of the human diet. Interest in anthocyanins has increased widely during the past decade. Numerous studies have suggested that anthocyanins have a wide range of health-promoting properties. These compounds are therefore considered to be a functional food factor, which may have important implications in the prevention of chronic diseases. The aim of this body of work is to investigate and review the current literature on anthocyanins, and particularly their pharmacokinetics and any health-promoting properties, in order to summarize existing knowledge and highlight any aspects that require further study and analysis.
Available from: Roger Wolfs
- "We showed the protective effect of vitamin B1 on OAG to be independent of IOP. This is in agreement with the association between vitamin B1 deficiency and degeneration of ganglion cells of the brain and spinal cord in animal experiments , and between vitamin B1 deficiency and a reduced thickness of the retinal ganglion cell layer in rats . Furthermore, a link between vitamin B1 deficiency and other optic neuropathies is well established . "
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ABSTRACT: Open-angle glaucoma (OAG) is the commonest cause of irreversible blindness worldwide. Apart from an increased intraocular pressure (IOP), oxidative stress and an impaired ocular blood flow are supposed to contribute to OAG. The aim of this study was to determine whether the dietary intake of nutrients that either have anti-oxidative properties (carotenoids, vitamins, and flavonoids) or influence the blood flow (omega fatty acids and magnesium) is associated with incident OAG. We investigated this in a prospective population-based cohort, the Rotterdam Study. A total of 3502 participants aged 55 years and older for whom dietary data at baseline and ophthalmic data at baseline and follow-up were available and who did not have OAG at baseline were included. The ophthalmic examinations comprised measurements of the IOP and perimetry; dietary intake of nutrients was assessed by validated questionnaires and adjusted for energy intake. Cox proportional hazard regression analysis was applied to calculate hazard ratios of associations between the baseline intake of nutrients and incident OAG, adjusted for age, gender, IOP, IOP-lowering treatment, and body mass index. During an average follow-up of 9.7 years, 91 participants (2.6%) developed OAG. The hazard ratio for retinol equivalents (highest versus lowest tertile) was 0.45 (95% confidence interval 0.23-0.90), for vitamin B1 0.50 (0.25-0.98), and for magnesium 2.25 (1.16-4.38). The effects were stronger after the exclusion of participants taking supplements. Hence, a low intake of retinol equivalents and vitamin B1 (in line with hypothesis) and a high intake of magnesium (less unambiguous to interpret) appear to be associated with an increased risk of OAG.
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