Age-related macular degeneration: prevention and treatment. A review

• Main Author: K. A. Mirzabekova
• Format: Article
• Language: Russian
• Published: Ophthalmology Publishing Group 2014-07-01
• Series: Oftalʹmologiâ
• Subjects: amd; antioxidants; lutein; zeaxanthin.
• Online Access: https://www.ophthalmojournal.com/opht/article/view/18

Age-related macular degeneration (AMD) is a multifactorial disease. Age, light exposure, smoking, melanin levels and low-antioxidant diet are contributed to AMD development and progression. Cardiovascular disorders are of considerable importance as well. In macula, photoreceptor outer segments that are rich in polyunsaturated fatty acids (FA), particularly, docosahexaenoic acid (DHA), are susceptible to free radicals damage. High blood flow velocity and oxygen partial pressure as well as direct sunlight exposure induce oxidative processes. The source of free radicals in photoreceptor cells and retinal pigment epithelium (RPE) is an extensive mitochondrial metabolism, photoreceptor outer segments phagocytosis, lipofuscin phototoxic activity and hemoglobin or protoporphyrin precursors photosensitization. Oxidative stress is considered as an universal component of cell depth in necrosis, apoptosis and toxic damage. Antioxidant protective system consists of enzymes (superoxide dismutase, glutathione peroxidase and catalase) and non-enzymatic factors (ascorbic acid, alpha tocopherol, retinol, carotenoids). Specific antioxidant food supplement containing ascorbic acid (500 mg), vitamin E (400 IU) and beta carotene (15 mg) coupled with zinc (80 mg of zinc oxide) and copper (2 mg of copper oxide) results in 25 % decrease in late-stage AMD development rate. Amongst the agents that can protect retina from oxidative stress and AMD development, carotenoids are of special importance. Lutein and zeaxanthin containing in retina and lens screen blue light from central area of the retina. They also absorb blue light and inhibit free radicals generation thus preventing polyunsaturated FA light destruction. Association between lutein and zeaxanthin intake and late-stage AMD risk was revealed. Amongst the most important factors which deficiency favors macular degeneration are omega-3 FAs, i.e., DHA. DHA is the key component of visual pigment rhodopsin transformation. It requires for nerve impulse generation.