Age-related macular degeneration (AMD) is an eye disease that can get worse over time. It is the leading cause of severe and permanent vision loss among people over the age of 60.
It is caused when the small central part of your retina, called the macula, wears down. The retina is the light-sensitive nervous tissue located at the back of the eye.
Because the disease occurs with age, it is often called age-related macular degeneration. It is usually not the cause of blindness, but it can cause serious vision problems.
Similarly, another form of macular degeneration, called Stargardt disease, affects children and young adults.
Wet or dry macular degeneration
There are two main types of degeneration:
- Dry form. The affected individuals may have deposits of yellow in their macula. As they get larger and more numerous, they can cloud or distort your vision, especially when reading. As the condition worsens, the light-sensitive cells in your macula thin out and eventually die.
- Wet form. Blood vessels grow under your macula and send blood and fluid to your retina. Your vision is distorted so that straight lines appear wavy. You may also have blind spots and loss of central vision. These blood vessels and their bleeding can eventually scar, leading to permanent loss of central vision.
Most people with degeneration have the dry form, but the dry form can lead to the wet form. Only about 10% of sufferers have the wet form.
Macular Degeneration Symptoms
At first, you may not have any noticeable signs of macular degeneration. It is possible that it will not be diagnosed until it gets worse or affects both eyes.
Symptoms of macular degeneration can include:
- Worse or less clear vision. Your vision may be blurry and it may be difficult to read fine print.
- Dark, blurry areas in the center of your vision
- Difficult or different perception of colors (rare phenomenon)
Possible causes
Age-related macular degeneration is more common in older people. It is the leading cause of severe vision loss in adults over 60.
It may be of genetic origin. If someone in your family has it, your risk could be higher.
Smoking, hypertension or high cholesterol, obesity, saturated fat consumption, fair skin, being female, and having a light eye color are also risk factors.
How is macular degeneration diagnosed?
A routine eye exam can detect age-related macular degeneration. One of the most common early signs is the presence of yellow spots under the retina. Your doctor can see them when they examine your eyes.
Your doctor may also ask you to look at an Amsler grid, a pattern of straight lines that looks like a checkerboard. Certain lines may appear wavy or you may notice that some lines are missing, which could be a sign of the disease.
If your doctor discovers age-related macular degeneration, you may need to undergo a procedure called angiography. The doctor injects a dye into a vein in your arm. They take photographs as the dye travels through the blood vessels in your retina. If there are vessels that send fluid or blood to your macula, the photos will show their exact location and type.
What treatments are available for macular degeneration?
There is no cure for macular degeneration. Treatment can slow it down or prevent you from losing your sight too quickly. Your options may include:
- Anti-angiogenesis drugs. These drugs block the creation of blood vessels.
- Laser therapy. High-energy laser light can destroy abnormal blood vessels growing in your eye.
- Photodynamic laser therapy. Your doctor injects a light-sensitive drug into your bloodstream, which is absorbed by abnormal blood vessels. Your doctor then sends a laser into your eye to trigger the drug and damage those blood vessels.
- Low vision aids. These are devices that help people make the most of their remaining vision.
Prevention
A large study found that some people with dry AMD could slow the disease by taking supplements of vitamins C and E , lutein, zeaxanthin, zinc, and copper.
Outlook for people with macular degeneration?
People rarely lose all their vision due to age-related macular degeneration. Their central vision may be poor, but they are still able to do many normal daily activities.
The dry form tends to get worse slowly, so you can keep most of your vision.
The wet form is one of the main causes of permanent vision loss. If it’s in both eyes, it can affect your quality of life.
Wet macular degeneration may require repeated treatments.
Underdiagnosed age-related macular degeneration
One in four cases of age-related macular degeneration is not identified early, according to a study published in 2017. Stricter detection standards must be put in place.
644 60-year-olds participating in a study had an eye exam during which no abnormalities were detected.
However, when they were re-examined by a research team from the University of Alabama at Birmingham (USA), about 25% of them showed signs of age-related macular degeneration.
« It is imperative that tougher standards are put in place to detect this disease. » Careful inspection of the macula of the eye (the center of the retina) is necessary to determine if signs of this disease are present in the patient”.
If age-related macular degeneration is suspected, many things can be done. Dietary change and the use of nutritional supplements can significantly slow the progression of the disease. Source: Mark Fromer et al. JAMA Ophthalmology, April 2017.