Macular degeneration, also called age-related macular degeneration or AMD, occurs when the central part of the retina, known as the macula, deteriorates. The macula allows us to see fine details and is needed in order to recognize faces, read, watch television, use a computer or drive a car. AMD is very common among older adults and is the leading cause of vision loss in the US with over 10 million Americans affected by this condition.
Macular degeneration normally progresses slowly causing gradual vision loss but in rare cases vision loss can happen suddenly. Macular degeneration usually affects central vision and early signs include shadowy, dark spots in vision, distorted vision where straight lines may appear wavy, blurred vision or partial loss of vision.
Classifications of AMD
There are two ways that macular degeneration is classified; either dry or wet. Dry macular degeneration is much more common accounting for 85-90% of cases while wet macular degeneration only accounts for 10-15% of diagnoses.
Dry macular degeneration, also known as atrophic or non-neovascular macular degeneration, occurs when there is a breakdown of the cells in the macula. The thinning of these cells as well as the presence of drusen, which are yellow protein deposits under the retina, affect central vision and color perception.
Wet macular degeneration is also referred to as exudative or neovascular macular degeneration. All wet AMD cases start as dry AMD even if no symptoms are initially present. Wet AMD is catergorized by the growth of abnormal blood vessels, that are fragile and frequently leak or bleed, that grow as a response to a disruption to the flow of oxygen to the macula that is caused by the breaking of membranes in the retina. Permanent damage to retinal cells occurs due to the leaking vessels and this creates blind spots in central vision.
How’d I get this?
Although macular degeneration is believed to be connected with aging, the exact causes are still unknown. Researchers believe that along with aging, a combination of genetics and environmental factors contribute to the development of this condition. Studies have found that there are specific genes present in most people with macular degeneration and people with lighter eye colors are believed to be more at risk for developing this condition. Other factors believed to increase the risk of developing macular degeneration include smoking, obesity, high blood pressure and drug side effects.
It is important to discover macular degeneration as early as possible since there are treatments that can delay symptoms from progressing. A routine eye exam can detect macular degeneration and one of the most common signs of the disease that are detected by an eye doctor is the presence of drusen or yellow protein deposits under the retina. A doctor may also use an Amsler grid, which is a pattern of straight lines, to determine if you have macular degeneration. Some people with macular degeneration will see the straight lines on the grid as wavy or even notice that some lines appear to be missing.
If your doctor believes you have macular degeneration, there are a few exams that can be done to confirm the condition. An OCT is a photograph that shows a magnified 3D image of the retina and allows your doctor to measure the different layers of the retina in order to aid in determining treatment options. Another procedure called a fluorescein angiography gives your doctor a closer look at the blood vessels in the retina. During the procedure, a dye is injected into the arm and once the dye reaches the eye photographs will show the exact location of any blood vessels leaking blood or fluid in the macula.
Next Steps: What can you do?
Treatment for macular degeneration depends on which form of the disease you have. Currently, there are no treatments for dry AMD but it is believed that nutrition may play a large role in preventing the disease from progressing to wet AMD. Vitamin C, vitamin E, lutein, zeaxanthin and zinc oxide are thought to be beneficial in reducing the risk of developing late stage AMD. It is important to note that these supplements will not cure macular degeneration or improve vision loss already caused by the disease and it is best to consult with your doctor prior to starting any sort of treatment.