Age-related Macular Degeneration
Stages of AMD
What are the stages of AMD?
There are three stages of AMD defined in part by the size and number of drusen under the retina. It is possible to have AMD in one eye only, or to have one eye with a later stage of AMD than the other.
- Early AMD. Early AMD is diagnosed by the presence of medium-sized drusen, which are about the width of an average human hair. People with early AMD typically do not have vision loss.
- Intermediate AMD. People with intermediate AMD typically have large drusen, pigment changes in the retina, or both. Again, these changes can only be detected during an eye exam. Intermediate AMD may cause some vision loss, but most people will not experience any symptoms.
- Late AMD. In addition to drusen, people with late AMD have vision loss from damage to the macula. There are two types of late AMD: geographic atrophy (also called dry AMD) and neovascular AMD (also called wet AMD).
- In geographic atrophy (also called dry AMD), there is a gradual breakdown of the light-sensitive cells in the macula that send visual signals to the brain, and of the supporting tissue beneath the macula. These changes cause vision loss.
- In neovascular AMD (also called wet AMD), abnormal blood vessels grow underneath the retina. (“Neovascular” literally means “new vessels.”) These vessels can leak fluid and blood, which may lead to swelling and damage of the macula. The damage may be rapid and severe, unlike the more gradual course of geographic atrophy. It is possible to have both geographic atrophy and neovascular AMD in the same eye, and either condition can appear first.
If You Are At Risk
AMD has few symptoms in the early stages, so it is important to have your eyes examined regularly. If you are at risk for AMD because of age, family history, lifestyle, or some combination of these factors, you should not wait to experience changes in vision before getting checked for AMD.
Does Early AMD Lead to Late AMD?
Not everyone with early AMD will develop late AMD. For people who have early AMD in one eye and no signs of AMD in the other eye, about five percent will develop advanced AMD after 10 years. For people who have early AMD in both eyes, about 14 percent will develop late AMD in at least one eye after 10 years. With prompt detection of AMD, there are steps you can take to further reduce your risk of vision loss from late AMD.
If you have late AMD in one eye only, you may not notice any changes in your overall vision. With the other eye seeing clearly, you may still be able to drive, read, and see fine details. However, having late AMD in one eye means you are at increased risk for late AMD in your other eye. If you notice distortion or blurred vision, even if it doesn’t have much effect on your daily life, consult an eye care professional.