Macular degeneration
Overview
Macular degeneration, also known as age-related macular degeneration (AMD), is a medical condition that results in a loss of vision in the center of the visual field due to damage to the retina. It is a major cause of visual impairment in older adults (>50 years). Macular degeneration can make it difficult or impossible to read or recognize faces, although enough peripheral vision remains to allow other activities of daily life.
Types
There are two types of AMD: dry (non-neovascular) and wet (neovascular). Neovascular refers to growth of new blood vessels in an area, such as the macula, where they are not supposed to be.
Dry AMD
Dry AMD is a chronic eye disease that causes vision loss in the center of your field of vision. Dry AMD is marked by deterioration of the macula, which is the part of the retina responsible for central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. Dry AMD generally affects both eyes. If only one eye is affected, you may not notice any changes in your vision because your good eye may compensate for the weak eye.
Wet AMD
Wet AMD is when new, abnormal blood vessels grow under the retina. These vessels may leak blood or other fluids, causing scarring of the macula. You lose vision faster with wet AMD than with dry AMD. Many people don't realize they have AMD until their vision is very blurry. This is why it is important to have your doctor examine your eyes regularly.
Symptoms
In the early stages, macular degeneration may not have symptoms and is known as early AMD. This can be detected with a regular eye exam that includes an examination of the retina. Regular comprehensive eye exams can detect early signs of macular degeneration before the disease leads to vision loss.
As macular degeneration develops, clear, normal vision (shown left) becomes impaired by a general haziness. This hazy vision will often continue to worsen over time.
Causes
The specific factors that cause macular degeneration are not conclusively known, and research into this little understood disease is limited by inadequate funding. At present, what is known about age-related Macular Degeneration is that the causes are complex, but include both heredity and environment. Scientists are uncertain about the precise mechanisms, but they involve the formation of drusen (tiny yellow deposits under the retina).
Risk Factors
There are many risk factors for macular degeneration, including age, smoking, and genetics. Other risk factors include race, as macular degeneration is more common in Caucasians than in African-Americans or Hispanics/Latinos. High blood pressure, obesity, and a diet high in unsaturated fats and simple carbohydrates also increase the risk of developing AMD.
Diagnosis
Macular degeneration is diagnosed by a comprehensive eye exam. This exam includes having drops placed in your eyes to enlarge, or dilate, the pupils. A dilated eye exam allows your ophthalmologist to view the back of the eye and the retina. If your ophthalmologist detects AMD, the next step is to determine if the disease is the dry or the wet form.
Treatment
There is no cure for macular degeneration, but it can be treated with vitamins, laser therapy, medications, and vision aids. The specific treatment recommended will depend on the type of macular degeneration (wet or dry) and the stage of the disease.
Prevention
While there is no surefire way to prevent macular degeneration, there are steps you can take to reduce your risk. This includes regular exercise, a healthy diet, and not smoking. Regular eye exams are also crucial for catching the disease early and starting treatment as soon as possible.