Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is a disease of the retina, and is the leading cause of visual impairment in people over the age of 50. In macular degeneration, the macula deteriorates. This may cause objects to be distorted, dark spots to be seen, or central vision to be blurred. Peripheral vision is not affected, and people with macular degeneration are often able to continue their normal activities. There is no cure for macular degeneration, but there are several treatments that are often used to decrease the risk of vision loss due to the disease.
Dry AMD
Most people with macular degeneration have dry, or atrophic, macular degeneration. In dry macular degeneration, the macula breaks down and age spots form underneath it. These age spots are yellow in color and are called drusen. Dry macular degeneration typically does not cause severe vision loss, but central vision becomes blurred. Both eyes are usually affected by dry AMD, although the rate at which each eye progresses may differ.
Wet AMD
Wet macular degeneration, also known as exudative or neovascular AMD, is a more serious and aggressive form of macular degeneration. Between 10-20% of macular degeneration cases are wet. In wet AMD, new abnormal blood vessels grow underneath the macula. These vessels are known as choroidal neovascularization (CNV) and because of their fragile and abnormal shape, bleed and leak fluid. This causes the macula to lift and bulge, displacing it from its normal position. When the macula is displaced, central vision loss can occur rapidly. Choroidal neovascularization can be seen with a special test, called a fluorescein angiogram. Photocoagulation is not a cure for macular degeneration, but it does slow vision loss in patients with wet AMD. (see photocagulation) Photodynamic therapy (PDT) can preserve vision in suitable patients.
Macular degeneration may take years to develop, and during the early stages, may be hard to detect. However, if both eyes are affected, vision changes may be noted more quickly. The symptoms of both wet AMD and dry AMD are similar. Central vision may be blurry or dark, or there may be spots in the center of the patient’s vision. Objects may look distorted or smaller than they really are. Straight lines (such as door frames) may appear wavy, due to the distorted shape of the macula. Peripheral vision is not affected. In dry AMD, the symptoms may progress very slowly, and are therefore are hard to notice. In wet AMD, the onset of symptoms is sudden, and progression occurs quickly, leading to more severe central vision loss.
Prevention
A clinical study in 2001 sponsored by the National Eye Institute found that certain supplements are helpful in slowing the progression of AMD and decrease the chances severe vision loss. High dose combinations of antioxidants, zinc, vitamin C, vitamin E, and beta-carotene have been shown to reduce the risk of developing advanced AMD. Some studies have also shown that eating green, leafy vegetables decreases the risk of developing AMD. Although none of these vitamins or minerals cure AMD, they do slow down the advancement of the disease and may help to decrease vision loss. There are several different vitamin formulas available, and a retina specialist can recommend one that is right for you.
Regular eye exams are important in the detection of macular degeneration. There is no known cause of macular degeneration. Because AMD mostly often occurs as part of the aging process, those over the age of 60, and those with a family history of macular degeneration should get yearly eye exams. Smoking increases the risk of developing AMD, and it is recommended that smokers who have already developed the disease stop smoking in order to preserve their vision. Also, those who take certain drugs are more at risk for developing macular degeneration. Early detection of AMD is the best way to prevent further vision loss. Vision tests using an Amsler grid are a simple way to check for macular degeneration.
Low vision aids are devices designed to assist people whose vision cannot be improved by surgery or eye glasses. Many products are available, such as magnifying glasses, computer screens that magnify smaller objects, writing guides, talking computers, and more. Low vision aids make the simple tasks in life much easier for people with certain eye diseases. A retina specialist can help you find a low vision aid that is right for you.