What is Macular Degeneration?
Age-related macular degeneration (AMD) is a disease that blurs thecentral vision you need for reading and driving. AMD affects the macula, the part of the eye that allows you to see fine detail. There are 2 types of macular degeneration: wet and dry.
AMD is a leading cause of vision loss in Americans over 60.In some cases, AMD advances so slowly that people notice little change in their vision. In others, the disease progresses faster and may lead to a loss of vision in both eyes.
These photos show how macular degeneration can affect a person's vision.
What is wet AMD?
Wet AMD, or Advanced AMD, occurs when abnormal blood vessels behind the retina start to grow under the macula. These new vessel often leak blood and fluid. The blood and fluid raise the macula from its normal place at the back of the eye. Damage to the macula occurs rapidly.
With wet AMD, loss of central vision can occur quickly. Unlike dry AMD, the condition does not affect vision in stages. n early symptom of wet AMD is that straight lines appear wavy. If you notice this condition or other changes to your vision, contact your eye care professional at once.
What is dry AMD?
Dry AMD occurs when the light-sensitive cells in the macula slowly break down. This causes gradually blurring central vision in the affected eye. As dry AMD gets worse, a person may see a blurred spot in the center of his or her vision. Over time, as less of the macula functions, central vision is gradually lost in the affected eye.
Dry AMD generally affects both eyes, but vision can be lost in one eye while the other eye seems unaffected. Ninety percent of all people with AMD have this type. Scientists are still not sure what causes dry AMD.
The most common symptom of dry AMD is slightly blurred vision.For example, a person may have difficulty recognizing faces. or need more light to read. Another early symptom is drusen, which is defined below. Dry AMD generally affects both eyes, but vision can be lost in one eye while the other eye seems unaffected.
What are drusen?
Drusen are yellow deposits under the retina. They often are found in people over age 60.
Drusen alone do not usually cause vision loss. In fact, scientists are unclear about the connection between drusen and AMD. They do know that an increase in the size or number of drusen raises a person's risk of developing either advanced dry AMD or wet AMD. These changes can cause serious vision loss.
How does dry AMD develop?
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 no symptoms and no vision loss.
- Intermediate AMD. People with intermediate AMD have either many medium-sized drusen or 1 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 have a breakdown of light-sensitive cells and supporting tissue in the central retinal area. This breakdown can cause 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. You may have difficulty reading or recognizing faces until they are very close to you.
If you have vision loss from dry AMD in one eye only, you may not notice any changes in your overall vision. You may notice changes in your vision only if AMD affects both eyes. If blurriness occurs in your vision, see an eye care professional for a comprehensive dilated eye exam.
Can the dry form turn into the wet form?
Yes. All people who had wet form AMD had the dry form first.
The dry form can advance and cause vision loss without turning into the wet form. The dry form also can suddenly turn into the wet form, even during early stage AMD. There is no way to tell if or when the dry form will turn into the wet form.
Can advanced AMD be either the dry form or the wet form?
Yes. Both the wet form and the advanced dry form are considered advanced AMD. Vision loss occurs with either form. In most cases, only advanced AMD can cause vision loss.
People who have advanced AMD in one eye are at especially high risk of developing advanced AMD in the other eye.