Macular degeneration, a process that obstructs vision by initially damaging fragile capillaries in the eye, is the leading cause of blindness among people over age 60. Millions currently suffer from age-related macular degeneration [AMD]; up to 37 per cent of people over the age of 75 have some form of AMD, and by the age of 80, 25 per cent will have lost eyesight due to this disease.
One type of AMD occurs when the tiny vessels in the back of the eye are weakened, allowing blood to seep out and leaving the eye defenceless to damage from the sun's powerful rays. This can cause a dark spot that blocks - or, blurry lines that distort - anything in your field of vision.
There are two types of age-related macular degeneration: dry and wet. Dry AMD is the less severe of the two and accounts for 90 per cent of all cases. In dry AMD, yellowish spots called drusen begin to accumulate breaking down the eye's light-sensing cells and causing distorted vision. If dry AMD advances far enough, it can become wet AMD, so named because it arises when tiny, abnormal vessels begin to grow behind the retina. These vessels can leak blood and fluid that damage the macula - the small, highly sensitive and specialised central area of the retina - not to mention vision blockage that may occur. Seeping fluid leads to rapid and severe vision loss. Wet AMD almost always takes place in people who have already suffered dry AMD and usually results in legal blindness. Legal blindness is defined as visual acuity less than 20/200 or visual field restriction to 20 per cent or less.
AMD isn't the only threat to aging eyes.
Glaucoma and cataracts
Glaucoma, which is the most common cause of blindness in all age groups, affects the optic nerve and usually remains undetected until a significant amount of vision has been lost. Cataracts, too, are quite common, afflicting two-thirds of individuals over age 70 with the inability to focus.
Unfortunately, even in this age of medical progress, there are no cures for eye disease and resulting blindness. Cataract operations and laser surgery, for example, benefit only a minority of patients, and although they can delay vision loss, they cannot prevent it. Indeed, there was little hope for aging eyes - until now.
Luckily, we now know that the risk of eye disease can be reduced by controlling one simple factor in our lives: nutrition. Recent medical research indicates that specific anti-oxidants can lower the risk of eye disease and prevent macular degeneration, cataracts, and glaucoma from occurring. These anti-oxidants include vitamin E, vitamin C, and an amino acid called taurine.
However, the most important defenders of the eye are a class of compounds called the carotenoids, which include beta-carotene and, most notably, a versatile and potent nutrient known as lutein. Lutein appears to prevent the risk of macular degeneration and other eye illnesses by protecting the fragile back of the eye from harmful blue light.
Carotenoids are a group of anti-oxidants found in concentrated quantities in fruits and vegetables. There are two major classes of carotenoids: the carotenes, including beta-carotene, and the xanthophiles, such as lutein and zeaxanthin. While beta-carotene, which is responsible for the yellow and orange colour of foods like squash and carrots, is the most famed carotenoid, it is virtually absent in the eye. This is where lutein and zeaxanthin enter the picture.
Age-related macular degeneration occurs when cells break down in the macula, a yellow spot at the centre of the retina that is responsible for our clear, central, or focused vision. This breakdown process slowly and progressively destroys sight in the centre of the field of vision, although it does not affect peripheral vision.
How lutein works
Lutein and zeaxanthin work by accumulating in the macula and screening out harmful blue light that can damage the back of the eye [unlike ultraviolet light, which can also damage the eye, blue light is part of the visible spectrum, known as the short wave].
Although xanthophiles are found primarily in leafy and green vegetables, especially kale, spinach, peas, lettuce, and broccoli, they are actually yellow and orange in colour, a fact hidden behind the chlorophyll that gives these vegetables their rich, dark hue. By pigmenting the macula, lutein and zeaxanthin act like sunglasses, filtering out destructive rays from the daily onslaught of light waves. They also fight free radicals that threaten to impair our vision.
Are You at Risk?
Age. This is the main risk factor for AMD. Approximately 18 per cent of people between the ages of 55 and 64 have this disease; the risk increases as we get older.
Diet. Stay away from saturated fats and cholesterol, which are particularly instrumental in facilitating free radical reactions; alcohol can deprive the body of protective anti-oxidants. Take fruits and vegetables [4-5 servings a day]
Sunlight. Wearing sunglasses, or taking care to shield your eyes from constant sunlight, will reduce the deterioration of the macula.
Smoking. Smoking reduces the amount of free radical-fighting anti-oxidants in the eye, more than doubling the risk of AMD.
Heredity. If AMD is part of your family medical history, it might be in your best interest to focus on preventing it in the first place.
Gender. Women over 75 have twice the risk of developing AMD as men in the same age.
Eye colour. Individuals with light-coloured eyes [blue or green, for example] have a much higher risk for AMD than those with darker eyes.
Heart disease and diabetes. Good eyesight depends on proper blood flow through the eyes. High blood pressure, or other forms of heart disease, as well as diabetes, can increase a person's likelihood of getting AMD..
By taking a full complement of supplements including vitamins C, E, and A, selenium, zinc, taurine, and anti-oxidants like lutein and zeaxanthin, as well as eating a healthful diet filled with leafy greens and juicy fruits, you can keep your eyes alert and strong throughout life
- For general health: carotenoids, through leafy green vegetables, or supplement/s, 5-10 mg a day
- Special conditions: lutein. For AMD: 20 mg a day; for cataract/glaucoma: 5-20 mg a day. [Note: Speak to your therapist for supplements/doses that suit your individual needs best].
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