Age related macular degeneration, often called AMD or ARMD, is the leading cause of vision loss and blindness among Americans who are age 65 and older. Because people in this group are an increasingly larger percentage of the general population, vision loss from macular degeneration is a growing problem.
AMD is degeneration of the macula which is the part of the retina responsible for the sharp central vision needed to read or drive. Because the macula primarily is affected in AMD, central vision loss may occur.
Wet and Dry Forms of Macular Degeneration
Macular degeneration is diagnosed as either dry (non-neovascular) or wet (neovascular) Neovascular refers to growth of new blood vessels in an area, such as the macula, where they are not supposed to be.
Macular Degeneration mainly affects central vision, causing "blind spots" directly ahead.
Dry Macular Degeneration (non-neovascular)
- dry AMD is an early stage of the disease and may result from the aging and thinning of macular tissues, depositing of pigment in the macula or a combination of the two processes.
Dry macular degeneration is diagnosed when yellowish spots known as drusen begin to accumulate in and around the macula. It is believed thee spots are deposits or debris from deteriorating tissue.
Gradual central vision loss may occur with dry macular degeneration but usually is not nearly as severe as wet AMD symptoms. However, dry AMD through a period of years slowly can progress to late-state geographic atrophy (GA) - gradual degradation of retinal cells that also can cause severe vision loss.
A major National Eye Institute study (AREDS) has produced strong evidence that certain nutrients such as beta carotene (vitamin A) and vitamins C and E may help prevent or slow progression of dry maculr degeneration. These findings have led to development of a number of different AREDS nutritional formulas for macular degeneration prevention.
Eye doctors also recommend that dry AMD patients wear sunglasses with UV protection against potentially harmful effects of the sun.
Wet Macular Degeneration (neovascular)
- in about 10 percent of cases, dry AMD progresses to the more advanced and damaging form of the eye disease. With wet macular degeneration, new blood vessels grow beneath the retina and leak blood and fluid. This leakage causes permanent damage to light-sensitive retinal cells, which die off and create blind spots in central vision.
Choroidal neovascularization (CNV), the underlying process causing wet AMD and abnormal blood vessel growth, is the body's misguided way of attempting to create a new network of blood vessels to supply more nutrients and oxygen to the eye's retina. Instead, the process creates scarring, leading to sometimes severe central vision loss.
Age-Realted Macular Degeneration Symptoms and Signs
Age-related macular degeneration usually produces a slow, painless loss of vision. In rare caes, however vision loss can be sudden. Early signs of vision loss from AMD include shadowy areas in your central vision or unusually fuzzy or distorted vision.
Viewing a char of black lines arranged in a graph pattern (Amsler grid) is one way to tell if you are having these vision problems.
What causes Macular Degeneration?
Though macular degeneration is associated with aging, research suggests there also is a genetic component to the disease.
Who gets Age-Related Macular Degeneration?
Besides affecting older populations, AMD occurs in white and females in particular. The disease also can result as a side effect of some drugs, and it seems to run in families.
New evidence strongly suggest smoking is high on the list of risk factors for macular degeneration. Other risk factors for macular degeneration include having a family member with AMD, high blood pressure, lighter eye color and obesity.
Some researchers believe that over-exposure to sunlight also may be a contributing factor in development of macular degeneration, but this theory has not been proven conclusively. High levels of dietary fat also may be a risk factor for developing AMD.
How Macular Degeneration is Treated
There is as yet no outright cure for age-related macular degeneration, but some treatments may delay its progression or even improve vision.
Treatments for macular degeneration depend on whether the disease is in it early-stage, dry form or in the more advanced, wet form that can lead to serious vision loss. No FDA-approved treatments exist yet for dry macular degeneration, although nutritional intervention may help prevent its progression to the wet form.
For wet AMD, treatments aimed at stopping abnormal blood vessels growth include FDA-approved drugs called Lucentis, Eylea, Macugen and Visudyne used with Photodynamic Therapy or PDT. Lucentis has been shown to improve vision in a significant number of people with macular degeneration.
Nutrition and Macular Degeneration
Many researchers and eye care practitioners believe that certain nutrients - zinc, lutein, Zeaxanthin and vitamins A, C & E - help lower the risk for AMD or slow down the progression of dry macular degeneration. Benefits of high levels of antioxidants and zinc for halting or slowing development of macular degeneration have been widely report based on results released in 2001 from the Age-Related Eye Disease Study (AREDS) conducted by the National Eye Institute. Phase two of the AREDS study began in late 2005 to evaluate whether similar protective effects against AMD might be associated with other nutrients such as Omega-3 fatty acids or "good fats" and lutein and zeaxanthin found in green, leafy vegetables.