What is dry AMD?
Dry AMD occurs when the layer of cells beneath the retina, the retinal pigment epithelium, begins to deteriorate. This, in turn, affects the overlying retina, particularly the light-sensitive cone cells (responsible for central vision and color perception), gradually dulling and blurring central vision in the affected eye. Dry AMD tends to progress over a matter of years, more slowly than wet AMD. As dry AMD gets worse, a person may see a blurred or blank spot in the center of vision or notice a gradual decline in his/her ability to see fine print or detail in images. Gradually, as less of the macula functions, central vision in the affected eye may be lost. In some individuals, as dry AMD worsens, new blood vessels may begin to grow, and the condition can progress into wet AMD.24 The most common symptom of dry AMD is gradual blurring of vision. People with dry AMD may have difficulty recognizing faces or may need more light for reading and other tasks.
Dry AMD accounts for about 90 percent of all cases, and normally affects vision less than wet AMD. Dry AMD is sometimes called atrophic, nonexudative, or drusenoid macular degeneration. A characteristic of dry AMD is the accumulation of tiny protein and fat-containing “drusen” deposits in a thin layer of cells beneath the photoreceptors in the retina called Bruch’s membrane. The origin of drusen is unknown, but they may be from waste products of various cells and tissues of the retina. Drusen may interfere with the health of the macula, causing progressive degeneration of the photoreceptor cells. Drusen deposits can, however, be present without vision loss. Reduction in central vision from dry AMD occurs gradually over many years. Vision may even remain stable between eye examinations. People with dry AMD do not usually experience a total loss of central vision but tasks that require finely focused vision may become more difficult.
Most of the time, AMD will begin as the less severe dry type and, for approximately 80% of people, it will remain that way. Dry AMD can develop in one eye or both. The early stage of dry AMD usually begins with the appearance of drusen. Drusen are small white or yellowish deposits that begin to accumulate in one of the deepest layers of the retina due to a breakdown in its normal function. You will not be aware that these deposits are forming. As the retinal layer continues to break down, an abnormal amount of drusen begins to build up. This build-up begins to disrupt the layers above it, eventually damaging the layer of photoreceptor cells (the cells that receive visual images from the lens), resulting in “blank” or blind spots in your central visual field. As dry AMD progresses from early to late stage, more cells break down and begin to waste away. At the same time, drusen continues to build up and eventually, additional, larger blind spots are formed.
Most of the time, AMD will begin as the less severe dry type and for 85-90% of people, it will remain that way. Dry AMD can develop in one eye or in both eyes. The early stage of Dry AMD usually begins with the appearance of drusen. Drusen are small white or yellowish deposits that begin to accumulate in one of the deepest layers of the retina due to a breakdown in its normal function. You will not be aware that these deposits are forming. As the retinal layer continues to break down, an abnormal amount of drusen begins to build up. This build-up begins to disrupt the layers above it, eventually damaging the layer of photoreceptor cells (the cells that receive visual images from the lens), resulting in “blank” or blind spots in your central vision field. As Dry AMD progresses from early to later stages, more cells break down and begin to waste away. At the same time, drusen continues to build up and eventually, additional, larger blind spots are formed.
