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Senior Citizen's Guide to South Jersey

Age-Related Macular Degeneration

dry amd

Figure 1.

wet amd

Figure 2.

amsler grid

Figure 3.

optical coherence tomography

Figure 4.

fluorescein angiogram

Figure 5.

resolution of hemorrhage

Figure 6.

end stage scanning retina

Figure 7.

Age-related macular degeneration (AMD) is a hereditary disease of the center of the retina in the eye (analogous to the film in the camera) affecting seniors that can gradually destroy sharp central vision important during reading and driving. There are two forms of AMD: wet and dry. Dry AMD (Figure 1) occurs when the light sensitive cells in the macula are lost over time in a genetically predisposed individual (especially when that individual is exposed to tobacco). There usually is no vision loss associated with dry AMD, but dry AMD may convert to the more significant, wet form of AMD. Wet AMD (Figure 2), responsible for nearly 90% of cases of vision loss in patients with AMD, occurs in a patient who initially has dry AMD when abnormally high levels of a specific growth factor (vascular endothelial growth factor -- VEGF) cause abnormal blood vessels to grow and leak under the macula.

A study in the year 2000 estimated that there were approximately 8,000,000 individuals with dry AMD and 1.2 million individuals with wet AMD in the United States. It is estimated that these figures would increase by 50% by the year 2020. AMD is estimated to cost the United States $30 billion each year. AMD can have a profound impact on the quality of life and can lead to depression in those affected by the disease.

Symptoms of AMD include blurred vision, with difficulty reading and recognizing faces. A common symptom of early wet AMD, is that straight lines appear wavy -- for instance, door frames may appear wavy, or curtain blinds may begin to look wavy rather than straight. An “Amsler Grid” is a self-test that an individual can give themselves to detect the “waviness” on a grid (Figure 3).

An ophthalmologist would suspect AMD In an individual over age 60 who has had recent changes in central vision. A complete eye exam would be performed, including using eye drops to dilate the pupil to enable an examination of the retina. In addition to the clinical examination, the ophthalmologist may perform a scan of the macula (an optical coherence tomography scan), which can detect swelling in the macula from leaking abnormal blood vessels (Figure 4). The ophthalmologist may also suggest a fluorescein angiogram, where pictures of the retina are taken after fluorescein dye is injected in the arm to detect the presence and leakage of abnormal blood vessels (Figure 5). The ophthalmologist may elect to send the individual to a retina specialist for further evaluation and treatment.

If there are signs of dry AMD, a specific high-dose formulation of antioxidants (500 mg vitamin C, 400 IU vitamin E., 15 mg beta-carotene -- equivalent to 25,000 IU vitamin A) with 80 mg zinc oxide and 2 mg copper oxide (the "age-related eye disease study" (AREDS) formula) significantly reduces the risk of advancing dry AMD and conversion to wet AMD and vision loss. This preparation was not found to benefit those with “low risk” characteristics, so an examination by an ophthalmologist would be the only way to determine whether such a preparation would be beneficial for any given individual. Prevention of exposure to tobacco is also very important to prevent progression.

If it is determined that an individual has the wet form of AMD, there are currently excellent treatments that may preserve or improve vision, especially if the disease is detected early (Figure 6). Antibodies to VEGF can be injected into an anesthetized eye to stop ongoing growth and leakage from the abnormal blood vessels associated with the wet AMD process. Once the swelling goes away, vision may actually improve in affected individuals. Multiple injections are necessary at this time, since no extended release preparation of these medications (Avastin (bevacizumab) and Lucentis (ranibizumab)) is available. Other medications are currently in development to be used alone or in combination with these preparations. Cold laser treatment (photodynamic therapy) can also be used to mechanically close the abnormal blood vessels.

Following resolution of the active phase of wet AMD, or as a result of progressive dry AMD involving the center of the macula the patient may be left with an area of thin macula and scarring centrally (Figure 7). Currently, much research is being done to try to regenerate the light sensitive cells that have been lost irreversibly as a result of this process. Until those therapeutics are available, low vision training and devices, including the implantable miniature telescope, are important to improve quality of life in patients who have been stabilized medically.

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