What is Macular Degeneration and Age-Related Macular Degeneration (AMD)?
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Macular Degeneration or Age-Related Macular Degeneration (AMD) is a gradual, progressive, painless deterioration of the macula and is the leading cause of vision loss and partial blindness in people who are 60+ years old in the U.S. AMD is referred to as such because it slowly develops as a person ages. Macular Degeneration very rarely leads to complete blindness but can cause severe vision loss over time.
The macula is the small area in the center of the retina that allows us to have detailed vision and is used while looking directly at an object to see it as clearly as possible. Our peripheral retina picks up everything else that surrounds the object that’s being focused on. Detailed vision is given by the macula and the peripheral retina gives a large area of vision that allows people to move through the world safely. This is why you may see someone with macular degeneration having trouble reading their mail but having no problems while spotting an object off to the side or in the distance, even in unfamiliar areas. It’s estimated that 10-15 million people in the U.S. have AMD, according to the American Academy of Ophthalmology.
“Dry” and “Wet” are the two main types of age-related macular degeneration. The majority of patients are diagnosed with the dry form and will not suffer from losing their central vision. However, the dry form of macular degeneration can lead to the wet form in some cases. Only about 10% of people with AMD develop the wet form but they also make up the majority of people who experience severe vision loss. It is the responsibility of people with macular degeneration to highly monitor their eyesight and make regular visits to the doctor.
- Dry-Form: “Dry” macular degeneration is characterized by the presence of drusen (yellow or white deposit accumulations of extracellular material) in the macula. The presence of a few small drusen is normal with advancing age and may not cause any changes to a person’s vision but if they grow in size and increase in number, they could lead to a dimming or distortion of the person’s vision; usually most noticeable when reading. During advanced stages of dry macular degeneration, a thinning of the light-sensitive layer of cells in the macula takes place and leads to atrophy (death of tissue). The atrophic form of dry macular degeneration may leave a person with blind spots right in the center of their vision and in advanced stages, patients can lose central vision all together.
- Wet-Form: “Wet” macular degeneration is characterized by choroidal neovascularization, the growth of abnormal blood vessels from the choroid underneath the macula. The blood vessels leak blood and fluid into the retina, causing distortion of vision and eventually leading to irreversible damage and rapid vision loss if left untreated. Wet macular degeneration is known to make straight lines look wavy, as well as cause blind spots and loss of central vision. The wet-form only accounts for about 10% of the total patients suffering from macular degeneration.
Risk Factors for Macular Degeneration
Macular degeneration is believed to be hereditary, meaning it can be passed on from parents to children. Although it hasn’t been proven, if you have family who has or had the condition, you may be at higher risk for developing macular degeneration. Talk to your eye doctor about your individual risk. Other risk factors for AMD include:
- Smoking
- High blood pressure
- High cholesterol
- Obesity
- Being Caucasian (Caucasians have a higher rate of developing AMD compared to others)
Symptoms of Macular Degeneration
In the early stages, someone with macular degeneration may not have symptoms and the condition may be unrecognized until it progresses or affects both eyes. If you or a family member experiences any of these symptoms, please see your ophthalmologist as soon as possible:
- Distortion of straight lines (can progress to a gradual loss of central vision)
- Dark, blurry areas or white-out in the center of vision
- Changes in color perception (diminished color perception)
Macular Degeneration Diagnosis
Age-related macular degeneration is typically detected during routine eye exams. A common early warning sign of macular degeneration is the presence of drusen (tiny yellow deposits under the retina). Drusen is easily identified by doctors during eye examinations.
Another common way doctors identify warning signs for macular degeneration is to ask patients to look at an Amsler Grid. An Amsler grid is a pattern of straight lines that resemble a chess or checkerboard. The grid can help identify those at risk of developing AMD. If some of the straight lines appear wavy or some of the lines are missing entirely; chances are the patient will be diagnosed with AMD.
When a doctor detects age-related macular degeneration, they may encourage a procedure called angiography. During the procedure a dye (fluorescein or indocyanine green) is injected into a vein in the arm. As the dye reaches the eye and flows through the blood vessels of the retina, photographs are taken. These photos will show the exact location and type of any new vessels or vessels that may be leaking fluid or blood in the macula.
Early detection of AMD is highly important. Treatments are available that can delay or reduce the severity of the disease.
Treatments for Macular Degeneration
While there is currently no cure for macular degeneration, there are several treatment options that can prevent severe vision loss or slow the progression of the disease considerably. These include:
- Anti-Angiogenesis Drugs: Medications that block the development of new blood vessels and leakage from the abnormal vessels within the eye that cause wet macular degeneration. Many patients report to have regained vision that was lost. However, the treatment may need to be repeated during follow-up visits.
- Vitamins: A 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 macular degeneration. Be sure to ask your eye doctor if vitamin supplements will benefit you before taking any.
- Laser Therapy: High-energy laser light can be used to eliminate actively growing abnormal blood vessels that occur in macular degeneration.
- Photodynamic Laser Therapy: A two-step treatment in which a light sensitive drug is used to damage the abnormal blood vessels. A doctor will then inject the drug into the bloodstream to be absorbed by the abnormal blood vessels in the eye. A cold laser is shown into the eye to activate the drug, damaging the abnormal blood vessels.
- Low Vision Aids: There are a ton of devices on the market today 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. See Magnifying Aids or Independent Living Aids.
Researchers are constantly looking for new treatments for AMD. The following treatments are considered experimental in the medical community and have been used less often since the development of anti-angiogenic medications.
- Submacular Surgery: Surgical procedure to remove abnormal blood vessels or blood.
- Retinal Translocation: A surgical procedure used to destroy abnormal blood vessels located directly under the center of the macula. The macular center is rotated away from the abnormal blood vessels to a healthy area of the retina, preventing the formation of scar tissue and further damage to the retina. Once the macular is moved away, a laser is used to treat the abnormal blood vessels.
Prevention
Currently there is no known way to prevent macular degeneration but some lifestyle factors can reduce your risk of developing the condition:
- Don’t smoke
- Eat a healthy diet high in fruits and vegetables (low in animal fat)
- Exercise regularly
- Maintain a healthy weight
- See your doctor regularly for dilated eye exams
Outlook for People with Macular Degeneration
Age-related macular degeneration rarely causes people to lose all of their vision. They may experience poor central vision, but they are still able to perform most normal daily activities.
The wet form of macular degeneration is a leading cause of irreversible legal blindness. When both eyes are affected, you may or may not experience a significant decrease in your quality of life. This usually depends on the persons’ personal perspective. There are plenty of legally blind people out there who enjoy the same quality of life as sighted individuals; minus the driving obviously.
The dry form of AMD is much more common and progresses more slowly, allowing people to keep the majority of their vision.
As unfortunate as it is, macular degeneration can recur after treatment. Because of this fact, individuals diagnosed with AMD need to follow the recommendations of their ophthalmologist and test their vision regularly. Proper and timely treatment(s) can slow the rate of vision loss and most often will improve overall vision.
