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MACULAR DEGENERATION: The back of the eye is similar to the film in a camera. Light focused on it is gathered by microscopic nerve cells and relayed to the brain via the optic nerve. The macula, located in the center of the retina, is the most sensitive part of the retina. It is tightly packed with color sensitive cells called "cone" cells. The cells of the macula are so tightly packed that there is little room for blood vessels, and this makes the area extremely dependent on nutritional support from blood vessels behind the retina. The retinal cells of the macula are responsible for fine detailed vision, such as for reading and seeing details in the center of the visual field.
When the sensitivity of the macula is reduced, the center of things you look at may look gray, hazy or "blocked out". Side vision is not affected by macular degeneration, even when it is very advanced.Because macular degeration tends to happen later in life, along with other systemic degenerative conditions, it is called "Age Related Macular Degeneration" or "ARMD". For people over the age of 60, ARMD is the leading cause of loss of vision.
No one fully understands why the macula tends to break down, but most researchers tend to blame the aging process. Just as the skin changes and tends to become thinner with age, and pigment migrates to form "age spots", so does the retina in the back of the eye, despite the fact that people who get ARMD seem otherwise in pretty good health.
ARMD seems to run in families, so heredity probably plays a role, but the most consistent finding among ARMD sufferers is the lack of certain nutritional elements in the macula, suggesting nutritional deficiency.
Many other factors have been studied by scientists, and it appears that smoking, excessive alcohol intake, elevated cholesterol levels, high blood pressure and other factors may also increase the risks, but the metabolic changes inherent in aging seem to be the major causative factors.Normal cellular metabolism, with the production of food and oxygen from nutrients in the blood, produces free radicals (hydrogen ions) which accumulate in tissue as waste products that can hurt healthy cells nearby.
Antioxidants to the rescue:
Antioxidants, chemicals with ring form which can capture free radicals, are important in the reduction of oxidants in tissue and are produced in moderate amounts by the body. More important is the supply of dietary antioxidants in the form of fresh fruit and vegetables, and additional vitamins and minerals in nutritional supplements now available.
Types of ARMD:
There are two major types of ARMD, called "dry" (atrophic) or "wet" (exudative). Most people have the dry type. This is a gradually developing degenerative condition in which the macula thins and small deposits called drusen build up under the surface.
In "wet" ARMD new blood vessels (subretinal neovascular membranes) grow in beneath the macula in an attempt to nourish it, and these vessels frequently break and leak, resulting in the "wet" appearance.Symptoms:
The first thing most people notice is that their central vision is blurred, making them think that they need stronger glasses. As time passes the central vision becomes more blurred, colors seem dim, and objects look like they are "shimmering", as if heat were rising off hot pavement. Straight lines appear wavy or slanted.
Any of the symptoms may be gradual or sudden. Sudden changes are indicative of the wet type, and call for immediate attention.The Medical Examination:
A complete eye examination will be done, including dilation and internal microscopic evaluation, possibly with Fluoreiscein Angiography, which involves injecting a dye intravenously followed by a series of photographs of the retina to determine the extent of leakage into the retina.
The Treatment:
Depending on the type and extent of degeneration of the retina, the treatment may involve nothing more than special antioxidant nutritional supplements, but could involve laser treatment of the involved area to seal leaking blood vessels. If detected early, and treated adequately with special vitamins and antioxidant supplements, some specialists believe that the progress of ARMD can be slowed or prevented.
If you have any further questions regarding macular degeneration, please consult your eye specialist.