What Is Macular Degeneration?
The term age-related macular degeneration (AMD) is used to describe a group of visual disorders that progressively destroy the cells located in the macula, the central portion of the retina. The light-sensitive cells of the macula generate the high-resolution and color vision we depend on for everyday activities, including reading, driving, and recognizing familiar faces. Damage to these cells has a dramatic impact on our ability to see and can cause complete blindness in the central visual field.
Visual impairment resulting from AMD may be first noticed by the patient or detected by an ophthalmologist during a routine eye exam. Degenerative changes to the macula can make straight lines appear blurry and distort the central visual field. A dark area or “black out” may appear in the center of vision, but peripheral vision often remains clear. Sometimes only one eye loses vision while the other eye continues to see well.
There are two main types of macular degeneration: “dry” and “wet.” Dry AMD is much more common, 85% of all people with intermediate and advanced AMD have the dry form. However, wet AMD accounts for more significant vision loss.
What is dry macular degeneration?
Dry macular degeneration is the most common type of AMD and vision loss is usually gradual. In fact, in early stages, changes in vision may be hard to notice. One may realize that straight lines appear wavy or notice blank spots in their central vision. Colors may look dim.
Dry AMD has three stages, all of which may occur in one or both eyes:
- Early Dry 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 Dry AMD: People with intermediate AMD have either many medium-sized drusen or one or more large drusen. Some people may 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 which 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.
Can the dry form turn into the wet form?
Yes. Everyone who has wet AMD had dry AMD first.
However, dry AMD can advance and cause vision loss without turning into wet AMD or can turn into wet AMD in the early stages. It’s critical to monitor AMD so you are aware of any changes.
What is wet macular degeneration?
Wet macular degeneration results when abnormal blood vessels from underneath the retina leak blood or fluid thus causing that portion of the retina to bulge. This bulging of the retina distorts vision and is characterized by 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. While only 10% of people with macular degeneration have wet AMD, it accounts for about 90% of the cases that lead to severe vision loss.
Where is the macula?
The macula is located in the center of the retina, the light-sensitive tissue at the back of the eye. The retina instantly converts light, or an image, into electrical impulses. The retina then sends these impulses, or nerve signals, to the brain.