What Is Age‐Related Macular Degeneration?
Age-related macular degeneration (AMD) is a deterioration or breakdown of the eye’s macula. The macula is a small area in the retina — the light sensitive tissue lining the back of the eye, it is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly. The macula makes up only a small part of the retina, yet it is much more sensitive to detail than the rest of the retina (called the peripheral retina). The macula is what allows you to thread a needle, read small print, and read street signs. The peripheral retina gives you side (or peripheral) vision. If someone is standing off to one side of your vision, your peripheral retina helps you know that person is there by allowing you to see their general shape.
Many older people develop macular degeneration as part of the body’s natural aging process. There are different kinds of macular problems, but the most common is age‐related macular degeneration. With macular degeneration, you may have symptoms such as blurriness, dark areas or distortion in your central vision, and perhaps permanent loss of your central vision. It usually does not affect your side, or peripheral vision. For example, with advanced macular degeneration, you could see the outline of a clock, yet may not be able to see the hands of the clock to tell what time it is. Causes of macular degeneration include the formation of deposits called drusen under the retina, and in some cases, the growth of abnormal blood vessels under the retina. With or without treatment, macular degeneration alone almost never causes total blindness. People with more advanced cases of macular degeneration continue to have useful vision using their side, or peripheral vision. In many cases, macular degeneration’s impact on your vision can be minimal.
When macular degeneration does lead to loss of vision, it usually begins in just one eye,though it may affect the other eye later. Many people are not aware that they have macular degeneration until they have a noticeable vision problem or until it is detected during an eye examination. Types of macular degeneration are dry macular degeneration and wet macular degeneration, otherwise known as non-exudative and exudative macular degeneration, respectively.
There are two types of macular degeneration:
Dry, or atrophic, macular degeneration (also called non‐neovascular macular degeneration)
Most people who have macular degeneration have the dry form. This condition is caused by aging and thinning of the tissues of the macula. Macular degeneration usually begins when tiny yellow or white pieces of fatty protein called drusen form under the retina. Eventually, the macula may become thinner and stop working properly. With dry macular degeneration, vision loss is usually gradual. People who develop dry macular degeneration must carefully and constantly monitor their central vision. If you notice any changes in your vision, you should tell your ophthalmologist promptly, as the dry form can change into the more damaging form of macular degeneration called wet (exudative) macular degeneration. Patients with dry macular degeneration may benefit from taking a vitamin suuplement, such as Preservision AREDS 2 Formula, made specifically to support the retina that is affected by macular degeneration.
If you have been diagnosed with macular degeneration, you should use a chart called an Amsler grid every day to monitor your vision, as dry macular degeneration can change into the more damaging wet form at any time.
To use the Amsler grid, wear your reading glasses and hold the grid 12 to 15 inches away from your face in good light.
- Cover one eye.
- Look directly at the center dot with the uncovered eye and keep your eye focused on it.
- While looking directly at the center dot, note whether all lines of the grid are straight or if any areas are distorted, blurry or dark.
- Repeat this procedure with the other eye.
- If any area of the grid looks wavy, blurred or dark, contact your ophthalmologist.
- If you detect any changes when looking at the grid, you should notify your ophthalmologist immediately.
Wet, or exudative, macular degeneration (also called neovascular macular degeneration)
About 10 percent of people who have macular degeneration have the wet form. It can cause more damage to your central vision than the dry form. Wet macular degeneration occurs when abnormal blood vessels begin to grow underneath the retina. This blood vessel growth is called choroidal neovascularization (CNV). These new blood vessels may leak fluid or blood, blurring or distorting central vision. Vision loss from this form of macular degeneration may be faster and more noticeable than that from dry macular degeneration.
The longer these abnormal vessels leak or grow, the more risk you have of losing more of your central vision. Also, if abnormal blood vessel growth happens in one eye, there is an increased risk that it will occur in the other eye. The earlier that wet macular degeneration is diagnosed and treated, the better chance you have of preserving some or much of your central vision. That is why it is so important that you and your ophthalmologist monitor your vision in each eye carefully.
Macular Degeneration Symptoms
In its earliest stages, people may not be aware they have macular degeneration until they notice slight changes in their vision or until it is detected during an eye exam. People who are at risk for macular degeneration should have regular eye exams to test for macular degeneration and, if diagnosed, begin treatment if appropriate.
Signs and Symptoms of Macular Degeneration
- Blurry distance and/or reading vision
- Need for increasingly bright light to see up close
- Difficulty seeing when going from bright light to low light (such as entering a dimly lit room from the bright outdoors)
- Trouble or inability to recognize people’s faces
- Blank or blurry spot in your central vision
- You may not notice vision changes if only one eye is affected, as your unaffected eye will compensate for vision loss in the other eye.
- Distorted vision — straight lines will appear bent, crooked or irregular
- Dark gray spots or blank spots in your vision
- Loss of central vision
- Size of objects may appear different for each eye
- Colors lose their brightness; colors do not look the same for each eye
- Wet macular degeneration symptoms usually appear and get worse fairly quickly.
Who Is at Risk for Macular Degeneration?
Genetic changes appear to be responsible for approximately half of individuals who acquire macular degeneration. People who have a close family member with the disease have a greater chance of developing macular degeneration themselves. Other risk factors for developing the disease, include smoking, high blood pressure, and UV light exposure.
Macular Degeneration Diagnosis
Many people do not realize they have a macular problem until they notice they have blurred or distorted vision. Regular eye exams by an ophthalmologist may help to detect problems or early stages of macular degeneration before you are even aware of them.
Macular Degeneration Treatment
Dry AMD and nutritional supplements
Unfortunately, there is no single proven treatment for the dry form of macular degeneration. However, a large scientific study has shown that antioxidant vitamins and zinc may slow the progression of macular degeneration in some patients. The Age-Related Eye Disease Study (AREDS and AREDS 2) showed that people at high risk for developing exudative macular degeneration benefited from taking a dietary supplement of vitamin C, vitamin E, zinc, antioxidants, and beta carotene. The supplement reduced the risk of patients developing exudative macular degeneration by about 25 percent. The daily supplements also reduced the risk of vision loss. The supplements did not appear to provide a benefit for people with minimal macular degeneration or people without evidence of the disease during the course of the study.
These vitamins and minerals are recommended in specific daily amounts in addition to a healthy, balanced diet. Some people may not wish to take large doses of antioxidants or zinc because of medical reasons. High doses of Beta carotene has been shown to increase the risk of lung and colon cancer in smokers or recent past smokers. It also contributes to loss of bone density. This supplement should not be used by people who currently smoke or recently quit smoking.
It is very important to remember that vitamin supplements are not a cure for macular degeneration, nor will they give you back vision that you may have already lost from the disease. However, specific amounts of these supplements do play an important role in helping some people at high risk for developing exudative AMD to maintain their vision.
Wet macular degeneration treatment
Treatment of the wet form of macular degeneration often involves the use of intraocular injections. The intraocular medication used and the frequency of these injections is determined by your retina specialist.
Prevention of macular degeneration
Eat a healthy diet, protect the eyes from UV light by wearing a hat and sunglasses, do not smoke, control blood pressure, and get regular eye exams.