Information on the causes and symptoms of macular degeneration.
Select a Topic
- What is Macular Degeneration?
- Diagnosing Macular Degeneration
- What Causes Macular Degeneration?
- Help for Macular Degeneration
- More Information on Macular Degeneration
What is Macular Degeneration?
Macular degeneration is a disorder that affects central vision – what you see directly in front of you as opposed to your peripheral or side vision. The macula is the central portion of the retina, the paper-thin tissue at the back of the eye where light-sensitive cells send visual signals to the brain, and is responsible for detailed vision.
Macular degeneration occurs when the central part of the retina deteriorates. Age-related macular degeneration (AMD or ARMD) is the most common eye disease and is in fact the leading cause of visual impairment and blindness in the United States in people over the age of 50.
Damage to the macula results in the development of blind spots and blurred or distorted vision and can hamper your ability to perform basic activities of daily living such as reading and driving.
Types of Macular Degeneration
Dry Macular Degeneration
Dry macular degeneration is the early stage of the disease. It may be caused by the aging and thinning of the macular tissues, the deposition of pigment in the macula, or by a combination of the two processes. Yellowish spots known as drusen begin to accumulate from these deposits or from the debris from deteriorating tissue, and this occurs primarily in the area of the macula. Loss of central vision may occur very gradually but can be as serious as the wet neovascular form of AMD.
Wet Neovascular Macular Degeneration
Approximately, 10% of dry AMD cases will progress to a more severe, advanced form of eye disease known as wet macular degeneration. Wet macular generation occurs when new blood vessels grow (neovascularization) beneath the retina and leak blood and fluid into the surrounding tissue.
The leakage of blood and fluid causes permanent damage to the light-sensitive retinal cells. These cells then die off and blind spots are created in the central vision. During the process of neovascularization, the body attempts to create a new network of blood vessels to supply more nutrients and oxygen to the eye's retina. This process fails and instead creates scarring that leads to a loss of central vision.
Wet forms of macular degeneration are further classified into two general sub-types – classic and occult. Classic choroidal neovascularization (CNV) is usually associated with severe vision loss. It occurs when blood vessel growth and scarring has very clear, delineated outlines observed beneath the retina. Occult neovascularization produces less severe vision loss and new blood vessel growth beneath the retina is not as distinctive and leakage is less obvious.
Diagnosing Macular Degeneration
The diagnosis of macular degeneration is based on an examination of the eye by an eye specialist or ophthalmologist. The initial tests include an examination of the retina as well as measurement of the sharpness of vision. A brief test using an Amsler grid that measures your central vision may be performed. A doctor may ask you about any symptoms of macular degeneration you are experiencing.
Tests to Diagnose Macular Degeneration
- Fluorescein angiography
This procedure involves a special dye that is injected into the arm and an ophthalmologist photographing the retina as the dye passes through.
Fluorescein angiography examines the retinal blood vessels surrounding the macular and will determine whether laser treatment is necessary
- Indocyanine green angiography
During this procedure infrared wavelengths are used to view the retina in order to help identify symptoms of macular degeneration that may not be detected with fluorescein angiography
- Optical coherence tomography (OCT)
This is a noninvasive examination technique that produces a cross-sectional image of the posterior retina.
This procedure uses the Rodenstock scanning laser ophthalmoscope and is used to quantify macular sensitivity and fixation pattern.
Symptoms of Macular Degeneration
- Slow, or in very rare cases a sudden, painless loss of vision are common symptoms of macular degeneration
- Blurred or shadowy areas in your central vision
- Blind spots
- Straight lines that when viewed look irregular or bent
- Objects appearing in a different color or shape (when viewed with each of the eyes)
What Causes Macular Degeneration?
The exact cause of macular degeneration is unknown but it is believed that aging, genetics as well as environmental factors all contribute to the onset of symptoms of macular degeneration.
Common Causes of Macular Degeneration
- Age – macular degeneration increases with age
- Race – although macular degeneration occurs in all races, it is more common in Caucasian individuals
- Gender – women have been found to be at higher risk of macular degeneration
- Family history – it has also been found that macular degeneration tends to be hereditary
- Exposure to sunlight
- High blood pressure
- Drug side effects
Help for Macular Degeneration
There is no cure for macular degeneration but some treatments may help to improve vision or delay the progression of symptoms of macular degeneration. Treatment does depend on the stage of the disease – whether macular degeneration is in the early stage, dry form or more advanced wet form.
Conventional treatments for dry macular degeneration may include nutritional supplementation such as Vitamin C, Vitamin E, beta-carotene with zinc and antioxidants to prevent free radicals or unstable oxygen from damaging the retina. The wet form of macular degeneration can lead to serious vision loss but there are various laser treatment options such as photodynamic therapy available to lessen the vision loss in the early stages.
More Information on Macular Degeneration
There are no proven methods to prevent macular degeneration but there are helpful ways to care for your eyes and to ensure good visual health.
Eye Care Tips
- Consult an ophthalmologist or eye specialist immediately if you experience any signs of vision loss.
- Use of the Amsler grid can help you to detect slight changes in your vision – this test helps you to monitor your vision daily in the comfort of your home.
- Stop smoking naturally, as smokers have a higher risk of developing macular degeneration.
- Eat a healthy balanced diet packed with leafy green vegetables.
- Protect your eyes from sun exposure by wearing sunglasses to block ultraviolet sunrays.
- Increase your intake of nutritional supplements such as antioxidants and zinc.
- People over 65 years should have regular vision exams that include screening for age-related macular degeneration.