Just as the name reflects, age-related macular degeneration (AMD) has been a severe eye disease among people over 65. The estimated number of AMD affected Americans is 3 million by 2020. As a part of the retina, macula is responsible for sharp and central vision, so that AMD may lead to vision loss.
There are generally two types: dry AMD and wet AMD, the former of which accounts for about 85-90 percent. Obvious symptoms of dry AMD include yellowish spots from deposits or debris from deteriorating tissue around the macula. Both macular tissue aging and thinning and pigment depositing can lead to dry AMD. Studies show that vitamin A, C and E may help prevent or slow progression of dry AMD. Dry AMD patients are also advised to wear sunglasses when outdoors. People with wet AMD have more severe problems: new blood vessels grow beneath the retina and leak blood and fluid, which damage light-sensitive retinal cells. Wet AMD is caused by the body’s misguided attempt to supply more nutrients and oxygen to the retina, which instead causes scarring and potential vision loss. Occult wet AMD has light blood leakage and less vision loss danger, while classic wet AMD has clear scarring and more vision loss danger.
If you have AMD, your central vision has shadowy areas. During a retinal exam, the doctor may detect early signs of AMD and then an Amsler grid can be used to measure your central vision. For a further affirmation, your retinal blood vessels surrounding the macula will be examined. Many researches have showed that macular degeneration is mostly caused by aging and eye tissue deterioration. Other confirmed or potential risk factors for AMD include drug side effects, smoking, family ADM history, high blood pressure, lighter eye color, obesity, over-exposure to UV lights, fat diet and so on.
AMD-affected people in their 90 develop vision loss at a possibility that is 15 times of that for people in their 60s. And overweight patients have a risk of advanced ADM that is double of that for people with normal body weight. Gene variants are also related to AMD, which is known as family disease. Smoking is reported to bring higher rates of vision loss on ADM patients. AMD occurs more frequently in whites, so that people with lighter eye color are suspected to suffer AMD at a higher incidence. Toxic drugs such as Aralen and phenothiazine may cause side effects that lead to AMD.
Currently, no outright cure is available for AMD. For dry AMD, FDA has never approved any treatment, although nutritional intervention may slow its progression. Those nutrients include zinc, lutein, zeaxanthin and vitamin A, C, and E. For wet AMD, FDA has approved drugs including Lucentis, Macugen and Visudyne to stop or slow abnormal blood vessel growth.
Since complete recovery from vision loss caused by ADM is impossible, regular Amsler grid tests are useful to detect underlying AMD risk. For people with vision loss, many low vision devices such as magnifying glasses are available.
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