What is Macular Degeneration?
Macular Degeneration (also known as AMD, or age-related macular degeneration) is an age-related condition in which the sensitive portion of the retina responsible for central vision, called the macula, begins to break down and no longer deliver clear visual images to the brain. Central vision is what we use to read, drive, and recognize faces. AMD is the leading cause of blindness in Americans aged 65 and older.
It is critical that people with macular degeneration visit their eye doctor on a regular basis to monitor their eyesight carefully.
There are two classifications of macular degeneration, dry AMD or wet AMD.
Dry Macular Degeneration
Dry AMD represents the early stages of the disease. This is the most common form of AMD, and accounts for 85% to 90% of all cases. Researchers believe it may result from the aging and thinning of macular tissues and/or the deposit of pigment in the macula.
A diagnosis of dry AMD is confirmed when yellow spots (called drusen) begin to accumulate in the macula. Deteriorating macular tissue is believed to be responsible for these deposits. Central vision loss is gradual during this stage of the disease.
Approximately 10% of Dry AMD cases will progress to Wet AMD.
Wet Macular Degeneration
Wet AMD represents the later, more severe stages of the disease. The body attempts to create a new network of blood vessels to support the macula, but instead ends up creating scar tissue and increased central vision loss. Unfortunately, the new vessels grow underneath the retina and leak blood and fluid, causing permanent damage to the light-sensitive cells in the retina.
Macular Degeneration Risk Factors
Risk factors for macular degeneration include:
- Family history of AMD
- High blood pressure
- High cholesterol
- High fat diet
- Caucasian descent
- Having a light eye color
- Side effect of some drugs
- Overexposure to sunlight
Symptoms of Macular Degeneration
Your eye doctor can detect early signs of macular degeneration before symptoms occur through a retinal examination. Early detection is important in order to begin treatment to limit the damage caused by this disease.
The early stages of AMD are usually painless and gradual, and often go unnoticed until it begins to cause permanent damage. The first sign of macular degeneration is generally a blurry, dim or dark area in the central area of your vision that gradually grows in size. Portions of your central vision may also appear fuzzy or distorted.
Symptoms of macular degeneration include:
- Dark, blurry areas in the center of vision
- Changes in the perception of color
Treatment for Macular Degeneration
There are treatments available for macular degeneration that may prevent severe vision loss or slow the progression of the disease considerably. Treatment options vary depending on the stage of the disease.
Treatment for Dry AMD
Currently there are a few treatments for dry macular degeneration undergoing clinical trials, seeking FDA approval.
In a large study performed by the National Eye Institute of the National Institutes of Health, it was found that for some people, vitamins C, E, beta-carotene, zinc, and copper can decrease the risk of vision loss in patients with intermediate to advanced dry macular degeneration:
Scientists found that people at high risk of developing advanced stages of AMD, a leading cause of vision loss, lowered their risk by about 25 percent when treated with a high-dose combination of vitamin C, vitamin E, beta-carotene, and zinc. In the same high risk group—which includes people with intermediate AMD, or advanced AMD in one eye but not the other eye—the nutrients reduced the risk of vision loss caused by advanced AMD by about 19 percent.1
The nutrients evaluated by the AREDS researchers contained 500 milligrams of vitamin C; 400 international units of vitamin E; 15 milligrams of beta-carotene; 80 milligrams of zinc as zinc oxide; and two milligrams of copper as cupric oxide (Copper was added to the AREDS formulations containing zinc to prevent copper deficiency, which may be associated with high levels of zinc supplementation).1
Treatment for Wet AMD
There are several FDA-approved drugs (Avastin, Eyelea, Lucentis, Macugen) designed to stop abnormal blood vessel growth and vision loss from wet macular degeneration. Many patients have actually regained vision that was lost. It is important to note that the treatment may need to be repeated.
In addition, laser treatment of the retina may be recommended. This high-energy light can sometimes be used to destroy actively growing abnormal blood vessels that occur in macular degeneration.
Another type of laser therapy, Photodynamic laser therapy, involves the use of laser light and a light-sensitive drug (Visudyne) to damage the abnormal blood vessels.