Age-related macular degeneration (AMD) is a leading cause of vision loss in the United States among people over age 65. The macula is the central portion of the retina containing the highest density of receptors. It is responsible for sharp vision associated with reading, watching TV or driving. There are two forms of macular degeneration, “wet” and “dry”. About 90% of people with AMD have the dry form in which there is a slow breakdown or thinning of the retinal pigment epithelial cells in the macula. These cells are important in maintaining the health and viability of the photoreceptors of the retina.
The wet form of AMD afflicts only 10% of sufferers, but accounts for 90% of the blindness caused by AMD. As the membrane beneath the retina thickens and breaks, new blood vessels grow. These new, fragile blood vessels leak fluid and blood causing damage to the retina, ultimately leading to a loss of central vision. There is currently no cure for AMD but research is being conducted to determine risk factors and develop effective treatments. Laser surgery, which destroys the abnormal blood vessel growth in the wet form of the disease, is an option. Two other treatments that have recently shown positive results are transpupillary thermotherapy and diode laser treatment following indocyanine green dye injection. It is important though, to detect and treat the disease before the vessels grow beneath the macula.
Some factors that may contribute to the development of AMD include exposure to the “blue rays” of the spectrum of sunlight (bright sunlight or reflection in the ocean or desert), hypertension, and smoking or exposure to second-hand smoke.
Some studies suggest that antioxidants help to maintain eye health and prevent disease. The research has focused on vitamin C, vitamin E, selenium and carotenoids. While the research looks promising, some data are inconclusive and further studies are needed.
Symptoms of AMD include:
- distortion of straight lines, with central vision appearing more distorted than peripheral vision.
- a dark, blurry area in the center of vision.
- change or decrease in color vision.
If you notice any of these symptoms it is important to see an ophthalmologist right away. As a regular practice, one should have periodic eye examinations by an ophthalmologist. Some diseases, AMD included, may have no symptoms initially, but damage can be detected during a thorough eye exam.