Dry AMD is the most common form of AMD and is characterized by the presence of yellow deposits, called drusen, in the macula. Vision loss is usually gradual, in fact, in the early stages of dry AMD, changes in vision may be hard to notice. As the drusen increase and grow in size, straight lines may appear wavy or it may look like there are blank spots in the center of vision. Colors may also begin to look dim.
Dry AMD has three stages, all of which may occur in one or both eyes:
- Early AMD. People with early AMD have either several small drusen or a few medium-sized drusen. At this stage, there are typically no symptoms and no vision loss.
- Intermediate AMD. People with intermediate AMD have either many medium-sized drusen or one or more large drusen. Some people see a blurred spot in the center of their vision. More light may be needed for reading and other tasks.
- Advanced Dry AMD. In addition to drusen, people with advanced dry AMD experience geographic atrophy, which is a gradual breakdown of the light-sensitive cells and supporting tissue in the central retinal area. This breakdown causes a blurred spot in the center of your vision. Over time, the blurred spot may get bigger and darker, taking more of your central vision.
Wet AMD (or neovascular AMD) is characterized by the growth of abnormal blood vessels underneath the retina. These blood vessels leak blood or fluid into the retina causing that portion of the retina to swell. This swelling of the retina distorts vision and can cause a sudden decrease in central vision. An eye with wet AMD will usually lose its ability to see fine detail; although prompt treatment may slow or minimize vision loss.
About 10-15% of individuals with macular degeneration develop the wet form.