Age-Related Macular Degeneration
Eye Diseases Benefit From Taking Supplements

Age-related Macular Degeneration, as its name suggests, is associated with the deterioration of macula functioning over the passage of time. Age-related macular degeneration is the most common cause of severe, irreversible, vision loss in elderly people. It is estimated that 20 to 25 million people suffer from this condition worldwide, of which 8 million people experience blindness. Therefore, it is very important to get your eyes checked regularly for detection of this dreaded condition. If you have noticed blurring or distortion of vision and you are above 60, you may be having macular degeneration!  During daily self-monitoring of vision, if you notice sudden blurring or black area in vision, you must report to your doctor immediately as timely intervention may halt the visual loss. Always follow the doctor’s advice regarding the frequency of eye check-up and anti-oxidant supplements religiously to prevent further damage.

To fully understand the implications of this condition, it is important to recognize just how critical the macula is for vision. The macula is the tiny central portion of the retina, the inner layer of the eye. The macula enables us to appreciate the finer details of any object, and to do subtle tasks such as reading, writing, sewing etc. It is responsible for central vision (what you see directly in front of you, rather than your peripheral vision), near vision, and color vision. This is possible because the macula is loaded with a large number of photoreceptive cones (special type of cells, stimulated by light). Even the slightest damage to the central part of the macula (fovea) causes profound disturbance to vision. 

Due to its importance, macular function is tested at every eye check-up. The doctor asks you to read a vision chart from a particular distance (usually 20 feet,) and notes the smallest line which you can read. This is known as your distance visual acuity. Normal visual acuity is 20/20. Macular function can also be self-monitored daily using the Amsler grid.

The main symptoms of age-related macular degeneration are a loss or blurring of vision, and a black area in the visual field (scotoma). Objects may appear distorted, small (micropsia), or large (macropsia).

There are two major types of age-related macular degeneration, dry and wet. Dry age-related macular degeneration starts with the development of tiny, yellow deposits in the macula. This ultimately results in the death of the nerve cells present in the macular area. The macula loses its normal yellow color, and appears white and lusterless.  Apart from anti-oxidants, there is no treatment for this type.

In wet age-related macular degeneration, abnormal, leaky, vessels grow in the macula, leading to the accumulation of blood and fluid. It is usually associated with severe vision loss.  Various treatments have been tried in this type of macular degeneration.  Drugs such as Avastin, Lucentis and Macugen stop the formation of the abnormal blood vessels and retard progression of vision loss. However, these drugs need to be given via injection into the eyes and are associated with various adverse effects such as infection, glaucoma (condition in which pressure of the eyes is raised).  In other method of treatment termed as photodynamic therapy, Visudyne (verteporfin), a dye is injected into the blood. This dye gets concentrated in the abnormal blood vessels which are then killed by using low-density lasers.  However, these treatment options are expensive, require multiple treatment sessions and have adverse effects. And still,  there is no guarantee that the vision loss will be halted.

Therefore, it is crucial to prevent the onset of age-related macular degeneration or halt it at an early stage.  Many eye diseases benefit from taking supplements, and anti-oxidant vitamin supplements for macular degeneration offer hope in this regard as they have the potential to prevent the occurrence or progression of this condition. To understand how anti-oxidants work, we need to know more about the pathogenesis of age-related macular degeneration.

The macula needs high levels of oxygen, and at the same time is continuously exposed to light. This promotes the formation of a large number of free radicals, which are highly reactive chemicals produced by the body as a part of normal metabolism. Free radicals are toxic and unstable compounds, and they cause retinal cell damage by damaging the DNA and the cell membranes.  Over a period of years, these free radicals injure the tissue cells in the macula, ultimately leading to degeneration.  They are produced in greater numbers when a person is exposed to UV radiation, tobacco smoke, and air pollution. The longer one lives, the higher the risk of acquiring this condition. According to one population-based study, age-related macular degeneration is present in approximately 46% of people aged 75 or above.. Although macular degeneration is closely related with the aging process, it is not inevitable with advancing age. This implies the involvement of other causative factors. These are hypertension, smoking, stress and dietary deficiency of antioxidants.

Anti-oxidants are nature’s best defense against free radicals. They act as scavengers and neutralize the free radicals, thereby limiting damage to the macula. Substances which act as anti-oxidants include vitamins (vitamins A, C and E), minerals (zinc and selenium), carotenoids (lutein and zeaxanthin), extracts from plants (bilberry and grape), etc.

Most anti-oxidants are not produced in the body and therefore have to be consumed in our diet or via nutritional supplements. Antioxidant supplements are best taken in the form of combination products, as multiple antioxidants in synergy work far more effectively than a single antioxidant. Latest studies indicate that a single antioxidant, even at high doses, does not provide the same degree of protection as a combination of antioxidants. Doses of multiple oxidants also help prevent the toxicity of a single agent.

Classification of anti-oxidants acting on the macula:

Carotenoids:

• Carotenoids, namely lutein and zeaxanthin, are yellow colored pigments derived from plants. They are present in very high concentration in the macula, giving it a yellowish color. They protect the cones from damage by free radicals, and also filter out blue light, which is highly damaging to photoreceptors. Thus, they act like "sunglasses", protecting the critically important central sight from damaging light waves. They also protect the blood vessels in the macular area. By virtue of these actions, they prevent the onset, and also retard the progression of age-related macular degeneration. Zeaxanthin is predominantly present in the center of the macula, while lutein is present on the periphery. This may imply that they have different functions and should be taken in combination.  Since carotenoids are not produced by the body, they need to be consumed in our diet or as nutritional supplements. Dietary sources of carotenoids include leafy green vegetables, corn, green peppers, carrots, peaches, and oranges. However, most people do not consume enough of these vegetables to provide 6 -10 mg of lutein per day, which is the minimum effective dose. Therefore, lutein and zeaxanthin supplements are necessary.  Most lutein supplements are derived from the extract of marigold flowers. One study found abnormally low levels of carotenoids in people suffering from age-related macular degeneration (Seddon et al, 1994). It is therefore quite possible that a carotenoid deficiency caused age-related macular degeneration in these people. A recent study found that visual acuity improved after daily supplementation of lutein for 12 months in patients with atrophic age-related macular degeneration (Richer et al. 2004). These studies make a compelling case for lutein and zeaxanthin supplementation for the prevention and treatment of age-related macular degeneration.

Plant extracts:

• Bilberry (Vaccinium myrtillus) is a small shrub found growing mostly in the fields of England, Scandinavia, and Siberia. The bilberry extract contains blue colored pigments called anthocyanins.  These are very powerful anti-oxidants and also protect the blood vessels in the retina by making them less fragile. By virtue of these actions, they could prevent age-related macular degeneration if taken regularly via nutritional supplements.  Grape seed extract is rich in another group of pigments called flavonoids, which also act as anti-oxidants and may help in age-related macular degeneration.

Minerals:

• Minerals such as zinc and selenium are used for the treatment of age-related macular degeneration due to their anti-oxidant properties. Zinc is highly concentrated in the macula. Zinc activates many enzymes and plays an important role in the metabolism of proteins and nucleic acids. Dietary sources of zinc include meat, poultry, fish, whole grains, and dairy products. One study found that the progression of age-related macular degeneration in patients was significantly retarded on oral zinc supplementation. For many years now, zinc has been used as a component in ocular nutritional supplements. Zinc does not have any significant adverse effects. However, zinc sulfate supplementation may depress copper levels and cause copper deficiency anemia. Therefore, zinc should always be taken with copper.

Vitamins:

• Vitamin E: Vitamin E is the main anti-oxidant vitamin as its function is to prevent the damage of body tissues by free radicals. In some age-related macular degeneration patients, blood vitamin E levels were found to be low, implying the need for supplementation. Due to its anti-oxidant properties, vitamin E is recommended by the National Institute of Eye (NIE) at a dose of 400 IU/day in the treatment of age-related macular degeneration. Selenium, a mineral, is required for the digestion and absorption of vitamin E. At the same time, vitamin E reduces selenium requirements by preventing selenium loss from the body. Thus, vitamin E and selenium act synergistically and reduce the body’s requirement for each other. Selenium also activates the antioxidant enzyme, glutathione peroxidase, and protects cell membranes from oxidative damage.
• Vitamin A: Vitamin A, the ‘eye vitamin’ is crucial for the generation of rhodopsin, the pigment present in photoreceptors. It also helps to maintain the transparency and luster of the cornea, the visible black portion of the eye. In addition to these actions, it has also found to possess anti-oxidant properties.
• Water Soluble Vitamins: Vitamin C and B₆ also act as anti-oxidants.

  Because of their anti-oxidant actions, vitamins A, C, E and B₆ are used for the prevention and treatment of age-related macular degeneration and are present in most ocular supplements.

Other Compounds:

• Alpha-lipoic acid: Alpha-lipoic acid, a fatty acid, acts as an anti-oxidant and also recycles and regenerates other antioxidants, including vitamin C and vitamin E.

Many early studies of low dose vitamin supplementation failed to the effectiveness of anti-oxidant supplements in age-related macular degeneration. The Age-Related Eye Disease Study (AREDS), the first study to use high doses of antioxidant vitamins and minerals, was conducted by the National Eye Institute, one of the National Institutes of Health. In this study, some patients with age-related macular degeneration received anti-oxidants plus zinc, whereas others received placebos. At the end of five years, it was found that the daily supplementation of anti-oxidants and zinc significantly retarded the progression of age-related macular degeneration. The daily supplement used in this study contained vitamin C 500 mg, vitamin E 400 IU and beta carotene 15 mg, zinc 80 mg and copper 2 mg. This combination was found to be free from significant adverse effects.  Based on the results of this high quality, double blind study, the American Academy of Ophthalmology recommended that patients with intermediate and severe age-related macular degeneration consider taking antioxidants plus zinc on a daily basis.

Anti-oxidants are free from serious side effects even if they are taken for a prolonged period provided the dose is proper. Sometimes, zinc may cause a gastrointestinal upset. Beta carotene was shown to increase the risk of lung cancer in smokers.

Conclusion: Age-related macular degeneration is a very common and dreaded disease of old age which may lead to irreparable vision loss. The treatment options are few, and not always successful in restoring vision. Certain eye diseases benefit from taking supplements, and anti-oxidants prevent damage to the macula by free radicals and are beneficial in retarding the progress of age-related macular degeneration. They also prevent the onset of age-related macular degeneration. Newer formulas containing lutein, zeaxanthin and other compounds may improve vision. Although anti-oxidants are found in various dietary sources, it is difficult to ingest a diet balanced in all the necessary anti-oxidants and the proper dose levels.

A scientifically formulated and comprehensive supplement like VisiVite i-Defense Gold Formula is vital to fill this lacuna in diet. The simple decision to supplement the daily diet with VisiVite i-Defense Gold Formula, especially above the age of 60 years, can play a vital role in preserving the eyesight in the years to come. This ideal ocular supplement includes all of the anti-oxidants described above, to give maximum protection against free radicals without causing adverse effects.

References:

1. Age-Related Eye Disease Study Research Group (2001) A Randomized, Placebo-Controlled, Clinical Trial of High-Dose Supplementation With Vitamins C and E, Beta Carotene, and Zinc for Age-Related Macular Degeneration and Vision Loss: AREDS Report No. 8. Archives of Ophthalmology 119, 1417–1436.
2. Klein R, Klein BE, Tomany SC et al (2002) Ten-year incidence and progression of age-related maculopathy: The Beaver Dam Eye Study. Ophthalmology 109, 1767-79..
3. Richer S, Stiles W, Statkute L, Pulido J, Frankowski J, Rudy D, Pei K, Tsipursky M, Nyland J (2004) Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial). Optometry 75, 216-30.
4. Seddon JM, Ajani UA, Sperduto RD et al (1994) Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. Eye Disease Case-Control Study Group. JAMA 272, 1413–20.
5. Chopdar A, Chakravarthy U, Verma D (2003) Age related macular degeneration. British Medical Journal 326, 485-5.

©2006, Vitamin Science Inc

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Vitamin Science, manufacturers of VisiVite nutritional supplements for eye health, such as VisiVite i-Defense Gold Formula (http://www.visivite.com/premier-eye-vitamin.html) has garnered frequent accolades in their development of vitamin supplements for macular degeneration, dry eye syndrome and in their public education regarding issues affecting senior eye health.