In the U.S., macular degeneration is the leading cause of severe vision loss in people over age 60. It occurs when the small central portion of the retina, known as the macula, deteriorates. The retina is the light-sensing nerve tissue at the back of the eye. Because the disease develops as a person ages, it is often referred to as age-related macular degeneration (AMD). Although macular degeneration is almost never a totally blinding condition, it can be a source of significant visual disability.
There are two main types of age-related macular degeneration:
Dry form. The “dry” form of macular degeneration is characterized by the presence of yellow deposits, called drusen, in the macula. A few small drusen may not cause changes in vision; however, as they grow in size and increase in number, they may lead to a dimming or distortion of vision that people find most noticeable when they read. In more advanced stages of dry macular degeneration, there is also a thinning of the light-sensitive layer of cells in the macula leading to atrophy, or tissue death. In the atrophic form of dry macular degeneration, patients may have blind spots in the center of their vision. In the advanced stages, patients lose central vision.
Wet form. The “wet” form of macular degeneration is characterized by the growth of abnormal blood vessels from the choroid underneath the macula. This is called choroidal neovascularization. These blood vessels leak blood and fluid into the retina, causing distortion of vision that makes straight lines look wavy, as well as blind spots and loss of central vision. These abnormal blood vessels eventually scar, leading to permanent loss of central vision. Unforturnately, the vision loss can be quite rapid In wet AMD.
Most patients with macular degeneration have the dry form of the disease and will not lose central vision. However, the dry form of macular degeneration can lead to the wet form. Although only about 10% of people with macular degeneration develop the wet form, they make up the majority of those who experience serious vision loss from the disease.
It is very important for people with macular degeneration to monitor their eyesight carefully and see their eye doctor on a regular basis.
As the name suggests, age-related macular degeneration is more common in older adults. In fact, it is the leading cause of severe vision loss in adults over age 60.
Macular degeneration may be hereditary, meaning it can be passed on from parents to children. If someone in your family has or had the condition you may be at higher risk for developing macular degeneration. Talk to your eye doctor about your individual risk.
Smoking, high blood pressure, high cholesterol, obesity, and being white are also risk factors for macular degeneration.
In its early stages, age-related macular degeneration may not have symptoms and may be unrecognized until it progresses or affects both eyes. The first sign of macular degeneration is usually distortion of straight lines. This may progress to a gradual loss of central vision.
Symptoms of macular degeneration include:
Straight lines start to appear distorted, or the center of vision becomes distorted
Dark, blurry areas or white out appears in the center of vision
Diminished or changed color perception
Difficulty reading – skipping letters or words, losing one’s place
If you experience any of these symptoms, make an office appointment as soon as possible.
There is no cure, but age-related macular degeneration treatments may prevent severe vision loss or slow the progression of the disease considerably. Several treatment options are available, including:
Anti-angiogenic drugs. These medications — injected into the eye — block the development of new blood vessels and leakage from the abnormal vessels within the eye that cause wet macular degeneration. This treatment has been a major change in the treatment of this condition and many patients have actually regained vision that was lost. The treatment usually need to be repeated on follow-up visits.
Laser therapy. High-energy laser light can sometimes be used to destroy actively growing abnormal blood vessels that occur in age-related macular degeneration.
Photodynamic laser therapy. This therapy is a two-step treatment in which a light-sensitive drug is used to damage the abnormal blood vessels. A medication is injected into the bloodstream to be absorbed by the abnormal blood vessels in the eye. The doctor then shines a cold laser into the eye to activate the drug, damaging the abnormal blood vessels.
Vitamins. A large study performed by the National Eye Institute of the National Institutes of Health, called AREDS — Age-Related Eye Disease Study — showed that for certain individuals, vitamins C, E, beta-carotene, zinc, and copper can decrease the risk of vision loss in patients with intermediate to advanced dry age-related macular degeneration. Ask if these vitamin supplements will benefit you before taking them.
Low vision aids. Devices that have special lenses or electronic systems that produce enlarged images of nearby objects. They help people who have vision loss from macular degeneration make the most of their remaining vision. Dr McGrew provides this service; please make an appointment to discuss your options