Age-related macular degeneration (AMD) affects the area of the retina called the macula. This small area is responsible for producing sharp, central vision required for "straight ahead" activities such as driving, reading, recognizing faces, and performing close-up work.
While scientists are uncertain of its cause, AMD destroys cells in the area of the macula in two different forms, "dry" and "wet." Dry AMD can advance so slowly that people hardly notice it, or it can rapidly progress to the "wet" type with vision loss in one or both eyes.
What is "Dry" AMD?
Dry AMD is associated with the slow deterioration of retinal cells in the macula, occurring in one eye or both eyes at the same time. The presence of drusen, tiny yellow deposits in the retina, is one of the earliest signs of AMD. Drusen can block nutrition that is needed by the eye. Over time, the retinal tissue can waste away causing spotty vision or even a moth-eaten appearance that leads to a progressive visual loss. Although the presence of drusen alone is not indicative of the disease, it may indicate the eye is at risk for developing more severe AMD.
What is "Wet" AMD?
Within the retina are layers of photoreceptors that are highly active and very sensitive. These photoreceptors require a lot of energy and a constant supply of nutrients. Anything that interferes with the flow of these nutrients can cause the macula to malfunction. In "wet" AMD, new blood vessels may form underneath the retina and cause the macula to malfunction. This can quickly destroy vision. In the beginning stages, straight lines appear wavy and fine details fade. It becomes hard to focus on just one word and faces start to blur. People gradually lose the ability to read or drive and may progress to legal blindness. Wet AMD occurs in only 10 percent of all cases, but it is responsible for 90 percent of decreased vision resulting from AMD.
Every year, more than 500,000 people worldwide lose their sight because of ‘wet’ AMD. In the United States alone, more than 1.6 million people are affected. There are more than 200,000 new cases each year, and experts expect that number to rise significantly as the baby boom generation ages and overall life expectancy increases. Fortunately, new medications are available to treat the problem and prevent vision loss.