- Dry Macular Degeneration
- Wet Macular Degeneration
- Summary and Recommended Supplements
from the Latin word, macula, meaning spot
The macula is the central and most vital area of the retina. It records images and sends them via the optic nerve from the eye to the brain. The macula is responsible for focusing central vision that is needed for seeing fine detail, reading, driving, and recognizing facial features.
Age-related macular degeneration (AMD) is the leading cause of blindness in people over the age of 55, affecting more than 10 million Americans. It is a condition in which the central portion of the retina (the macula) deteriorates. It is equally common in men and women and more common in whites than blacks. The cause is unknown, but the condition tends to run in some families. Macular degeneration affects more Americans than cataracts and glaucoma combined.
There are two forms of macular degeneration: atrophic (dry) and exudative (wet). Approximately 85-90% of the cases are the dry type. Both forms of the disease may affect both eyes simultaneously. Vision can become severely impaired, with central vision rather than peripheral vision affected. The ability to see color is generally not affected, and total blindness from the condition is rare.
There is little that can be done within conventional medical treatment protocols to restore lost eyesight with either form of the disease. Leading researchers, however, are documenting the benefits of a more holistic approach in the treatment of AMD. Patients are encouraged to increase physical fitness, improve nutrition (including a reduction in saturated fats), abstain from smoking, and protect their eyes from excessive light. Dietary supplementation of trace elements, antioxidants, and vitamins is recommended for improving overall metabolic and vascular functioning. Early screening and patient education offer the most hope for reducing the debilitating effects of the disease.Dry Macular Degeneration
- UV Sunlight and Smoking
In the dry type of macular degeneration, the retina deteriorates in association with the formation of small yellow pigment-like deposits, called drusen, that form under the macula. The formation of these deposits leads to a thinning and drying out of the macula. Vision loss is related to the location and amount of retinal thinning caused by the drusen.
The dry type of macular degeneration tends to progress more slowly than the wet type, with vision being lost painlessly. The first symptom is usually a distortion in one eye, causing straight lines to look wavy. Blank spots will occur as the macula continues to degenerate. A vision test will sometimes reveal physical deterioration before symptoms occur.The Benefits of Nutritional Supplementation
Nutrients that may improve microcapillary circulation in the eye and thus slow down deterioration of the macula include ginkgo biloba at 120 mg a day (Piovella 1973), grape seed-skin extract at 200-300 mg a day, and bilberry extract at 150 mg a day.
A double-blind, case-controlled study showed that those with macular degeneration had decreased intake of vitamin E, magnesium, zinc, vitamin B6, and folic acid. This study identified 14 specific antioxidant components that could stabilize, but not improve, dry macular degeneration when consumed for a period of 1.5 years (Richer 1996). Supplementation with the Life Extension Mix and Life Extension Booster formulas provides these specific antioxidant components. Also, Life Extension Mix and Booster contain other nutrients, such as lutein, which have been shown to prevent wet macular degeneration.
Hydergine in doses of 4-5 mg a day and higher has shown benefits in treating dry macular degeneration. The following antioxidant nutrients should also be considered: alpha-lipoic acid, 500 mg a day; and glutathione, 500 mg a day.
The standard daily dose of Life Extension Mix--3 tablets 3 times a day--provides adequate levels of vitamin B complex, zinc, and other nutrients that are crucial for ocular function.
Anyone with dry macular degeneration also should refer to the Wet Macular Degeneration section because those with dry macular degeneration are at a high risk of developing the more debilitating wet macular degeneration.The Effects of UV Sunlight and Smoking
The daily application of the vitamin A-based Viva Drops can provide antioxidant protection to the lens of the eye. Also, wraparound UV-blocking sunglasses provide significant protection against UV sun rays. Exposure to sunlight without wearing UV-blocking sunglasses is a risk factor in developing macular degeneration.
Cigarette smoking among women has been shown to increase the risk of macular degeneration by 2.4-fold, compared to women who never smoked. Those who quit smoking still had a twofold increased risk relative to those who had never smoked. Even among those who had quit smoking for 15 or more years, little reduction in risk was shown, compared with current smokers. Cigarette smoking has been determined to be an independent and avoidable risk factor for age-related macular degeneration among women (Seddon et al. 1996).Wet Macular Degeneration
- Free-Radical Damage
- Direct Application of Nutrients
In the wet type of macular degeneration, abnormal subretinal blood vessels grow under the retina and macula: this is known as angiogenesis. These newly formed blood vessels will bleed or leak, causing the macula to bulge or form a mound, often surrounded by small hemorrhages. Central vision will thus become distorted. Vision loss may be rapid and severe under these circumstances. Individuals with wet macular degeneration may see a dark spot or spots within their central vision due to the blood leakage under the retina. Because the macula is no longer smooth, straight lines will appear wavy.
Laser surgery may be recommended in the early stages of deterioration to save further vision loss. It is not always successful and may even cause scarring and additional vision loss. Successful laser surgery may slow the rate of vision loss and preserve some sight, but will not stop a recurrence. Low-dose radiation therapy has shown promising results in decreasing neovascularization associated with the disease (Schwartz et al. 1997).
Verteporfin (Visudyne) is a light-activated or photosensitive drug combined with a nonthermal or cold laser for the treatment of wet macular degeneration. In Phase III trials, Visudyne therapy was shown to preserve vision in a significant number of patients with the wet form of AMD. Visudyne therapy is also approved for pathologic myopia (nearsightedness) and ocular histoplasmosis (infection resulting in macular lesions).
Researchers at Johns Hopkins University, led by Dr. Neil M. Bressler, have reported that (Visudyne) has prevented vision loss in 61% of wet AMD patients receiving it in experimental trials (Bressler et al. 2000). Visudyne therapy is approved for the treatment of classic subforeal choroidal neovascularization (CNV) lesions. The lesion size must measure less than 5400 mcm at the time of treatment.The Benefits of Nutritional Supplementation
The phytochemicals that protect against wet macular degeneration are lutein and zeaxanthin (Beatty et al. 2000, 2001; Bone et al. 2000, 2001; Rapp et al. 2000; Landrum et al. 2001). Lutein is a pigment found in dark green leafy vegetables, including spinach, kale, broccoli, and collard greens. Zeaxanthin is found in fruits and vegetables with yellow hues such as corn, peaches, persimmons, and mangoes. Both lutein and zeaxanthin are present in the retina and positively affect macular pigment density. The denser the pigment, the less likely a retinal tear or degeneration will occur. Improvement has been seen in some test subjects after only one month's consumption.
Soy contains the phytochemical genistein that has antiangiogenesis properties (Lutty et al. 1997). Those with wet macular degeneration may want to take two 700-mg capsules 2 times a day of Ultra Soy Extract in order to obtain enough genistein to possibly inhibit blood vessel growth in the eye.
Also, there are several new antiangiogenesis drugs being developed, primarily to treat cancer. An FDA advisory panel has approved thalidomide to treat leprosy. Thalidomide is an extremely potent antiangiogenesis drug that could slow or possibly stop the progression of wet macular degeneration (Kaven et al 2001). It is legal for doctors to prescribe thalidomide to treat wet macular degeneration even though it will only be officially approved to treat leprosy.
Thalidomide causes severe birth defects and must not be used by pregnant women or women who may become pregnant.Protection Against Free-Radical Damage
Free-radical damage has been implicated in the development of wet macular degeneration. Zinc, vitamin C, and vitamin E deficiencies have been found in many people who develop wet macular degeneration (Ishihara et al. 1997; Brown et al. 1998). It should be noted that these vitamins have not yet been shown to slow the progression of the disease once it has been clinically manifested. The daily dose of Life Extension Mix--3 tablets 3 times a day--will provide broad-spectrum antioxidant protection against free-radical damage to the eye. An additional 30 mg of zinc should also be considered.
Omega-3 fatty acids have been proven to be essential for protection against macular degeneration as well as many other diseases (Smith et al. 2000; Seddon et al. 2001). Only oily fish contain adequate omega-3, not the mild white fish.
In a published study, Dr. Wayne Smith of Australian National University, Canberra, found that more frequent consumption of fish appeared to protect against late age-related macular degeneration. Interestingly, the greatest benefit was seen in those who ate 1 serving a week: more fish did not mean more protection (Smith et al. 2000). Furthermore, eating too much fish may interfere with the absorption of vitamin E in the elderly.Applying Nutrients Directly to the Eye
Oxidative stress that reduces blood flow to the eye and increases the level of free radicals is a contributing factor to both wet and dry macular degeneration. The aging eye may also fail to break down and remove old proteins resulting in the accumulation of nonfunctioning protein crosslinks known as glycation endproducts. Topical application of certain nutrients may help to prevent these factors that contribute to age-related eye disorders such as cataracts and macular degeneration.
Glutathione is an antioxidant found in large concentrations in the eye. Diminished levels of glutathione occur during aging, which makes the lens nucleus susceptible to oxidative stress-induced clouding (Giblin 2000). Vitamin C is highly concentrated in the aqueous humor and corneal epithelium. It has been shown to absorb ultraviolet radiation and prevent cataracts in a concentration-dependent manner (Brubaker et al. 2000). In combination with cysteine, an amino acid antioxidant, vitamin C is able to remain stable in an aqueous solution and acts as a precurser to glutathione synthesis.
L-carnosine is a naturally occurring antioxidant and antiglycation agent. In studies, topically applied N-acetyl-carnosine helped to prevent light-induced DNA strand breaks and even repaired damaged DNA strands (Specht et al. 2000).
Riboflavin monophosphate is a B complex vitamin that removes oxidized glutathione and helps to prevent sensitivity to light, loss of visual acuity, and burning and itching in the eyes (Lopez Bernal 1993). Taurine is an amino acid found in high concentrations in the retina. A deficiency of this amino acid alters the structure and function of the retina.Summary
Age-related macular degeneration is the leading cause of irreversible vision loss in the United States, occurring as a result of deterioration of the central portion of the retina known as the macula. Approximately 85-90% of the cases are of the dry type. Although the cause of AMD remains unknown, researchers continue to find a positive correlation between the onset of the disease with genetic susceptibility, the effect of normal aging, low levels of serum and dietary antioxidants, and low levels of lutein and zeaxanthin in the macula of the retina of the eye.
For more information, contact the Association for Macular Diseases, (212) 605-3719.
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