Age Related Macular Degeneration
Courtesy NIH National Eye Institute
Macular degeneration is a condition where the central portion of the retina called the macula degenerates in older individuals. The macula contains the photoreceptors that contribute to sharp central vision. Behind the thin layer of macula is the choroid or blood supply to the retina which is affected in the Wet-ARMD stage. ARMD begins as Dry-ARMD and progresses to Wet-ARMD in patients whom are usually over age 50.
Symptoms include blurred central vision, distorted central vision, loss of central vision, slow recovery after exposure to bright light, decreased contrast sensitivity, decreased ability to differentiate colors and decreased color vibrancy. Although ARMD can lead to central vision blindness, the peripheral or side vision usually remains intact.
Risk factors include increased age,light colored eyes, family history of ARMD, high sun exposure, high blood pressure, high cholesterol, high fat intake, and smoking whichmay be the greatest controllable risk factor.
Dry ARMD: Dry ARMD is very common and is the first and less severe stage of macular degeneration. The hallmark of ARMD is Drusen which are cellular debris that build up in the macula and underlying choroid. These drusen begin to coalesce lifting and breaking down the retina and resulting in blurry central vision.
Wet ARMD: Wet ARMD is much more severe and much less common than dry ARMD. Abnormal vessels grow beneath the retina in the choroid and leak fluid underneath the retina. This leaked fluid and scarred blood vessels damage photoreceptors in the macular area of the retina and may cause severe irreversible vision loss.
Amsler Grid: The Amsler Grid is an easy way for patients to monitor their macular health. Patients are to test one eye with their reading correction at a time from about 12 inches away looking at the center dot and note the rest of the grid. With normal eyes the chart should have straight evenly spaced lines with no missing lines. With macular disease a patient may see wavy, distorted, missing or bent lines. Patients are advised to check every day by hanging the grid on the refrigerator or bathroom mirror. If a patient sees wavy, distorted, missing or bent lines he should contact his Eye Care Professional immediately. At the bottom of the page is an Amsler Grid.
ARMD prevention includes exercise, a healthy diet including fruits, green leafy vegetables and Omega 3
Fatty Acids, and quitting smoking. Other theories such as the Alta Eficacia Method for ARMD prevention is to wear a filter that blocks blue and violet light from entering the eye. It has been shown that the macula prefers to absorb violet light which may contribute ARMD.
ARMD progression may be slowed by quitting smoking most of all. Other ways to slow progression include increased intake in Lutein, Zeaxathin, Omega 3 Fatty acids and vitamins. The Age Related Eye Disease Study found that a vitamin combination may reduce progression of intermediate ARMD to advanced ARMD.
Vitamin C- 500mg
Vitamin E- 400 IU
Vitamin A- 15mg (Vitamin A should be substituted for 10mg of Lutein in smokers since it may increase the risk of lung cancer)
Management of symptoms includes low vision devices such as magnifiers and text to speech programs.
Yellow Tints may help with glare.
Copying and pasting internet text to a word processor then increasing the font size and inverting the colors to white text on a black background will make it easier for patients with severe ARMD to read with less glare.
Web pages may be magnified in Internet Explorer, Mozilla Firefox and Google Chrome by pressing CTRL and + at the same time.
You can read more about which low vision devices may be useful for you here .
Dry ARMD: There is no treatment for Dry ARMD only ways to slow it down as seen in the management section above.
Wet ARMD: The most common treatment for Wet ARMD is injections into the eye of an Anti-VEGF drug. These injections cause regression of the abnormal blood vessels in Wet ARMD resulting in less leakage and less swelling in the macula. This allows vision to improve a few lines on the chart. These injections are usually given every month and do not permanently get rid of Wet ARMD.
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Photo used under Creative Commons from JLStricklin