Welcome to the AMD Resource Center, presented by the Angiogenesis Foundation. This animation will explain how wet AMD causes vision loss. Age-Related Macular Degeneration (AMD) is a disease that causes progressive damage to the macula, a central region of the retina. The retina is the light receiving nerve layer located in the back of the eye.
The macula contains the densest population of nerve cells, called photoreceptors, and is particularly important for seeing detail and maintaining the central part of our vision. Central vision is important for ordinary daily activities like reading, driving, dialing the telephone, and recognizing faces. The macula is composed of several layers of specialized cells. The photoreceptors sit atop a layer of cells called retinal epithelial cells (RPE). Underneath these layers is a thin lining called Bruch’s membrane. Beneath Bruch’s membrane is the choroid, a network of blood vessels that provide oxygen and nutrients to the macula. As the eye ages, debris from the RPE cell layer, and surrounding tissues accumulates above and within the Bruch’s membrane. The debris form deposits called drusen. The presence of drusen is usually the first sign of early dry AMD. As drusen accumulate, they can cause inflammation. Inflammatory cells are then recruited to the retina, and these cells, along with the RPE, begin releasing growth factors that cause blood vessels to grow. The primary growth factor released is called vascular endothelial growth factor (VEGF). The VEGF protein diffuses into the choroid, stimulating the growth of new blood vessels. This process is called angiogenesis. The new blood vessels sprout and grow into and through the weakened Bruch’s membrane. At this point, the condition progresses from dry AMD to a more serious form called wet AMD. These growing blood vessels are abnormally leaky, which allows fluid and blood to seep into the layers of the macula. Fluid accumulates between Bruch’s membrane and the layer of photoreceptors, damaging the delicate nerves required for vision. If left untreated, bleeding due to this condition can cause scarring of the macula and permanent vision loss. In the photos shown here, the first represents normal vision, while the second shows the effects of wet AMD. The most severe form of wet AMD causes central vision loss and can make daily tasks such as reading, driving, and recognizing faces impossible. Learn what you can do to detect this important health condition, and to preserve precious vision.