Macular Degeneration Overview:
Macular degeneration is a disease of the macula, an area of the retina at the back of the eye that is responsible for fine detail vision. It is a common disease that appears in older adults and is the leading cause of vision loss in patients over 50. Vision loss usually occurs gradually and typically affects both eyes at different rates. Even with a loss of central vision, however, color vision and peripheral vision may remain clear.
Types of Macular Degeneration
There are two forms of age-related macular degeneration. The first type is dry macular degeneration, also known as non-neovascular. The second type is wet macular degeneration, also known as neovascular.
Dry Macular Degeneration
The vast majority of patients have dry macular degeneration. Non-neovascular is considered the early stages of the disease and occurs as the macular tissue starts thinning or deteriorating. In addition, patients will experience the formation of abnormal yellow deposits called drusen. Progression of dry macular degeneration occurs very slowly and does not always affect both eyes equally.
Wet Macular Degeneration
Wet macular degeneration is the more advanced stages of the disease and only about 10 percent of patients progress to this stage. Neovascular macular degeneration occurs when abnormal or leaking blood vessels grow underneath the retina in the area of the macula. These changes can lead to distorted or blurred vision and, in some cases, a rapid and severe loss of straight-ahead vision.
Causes of Macular Degeneration
- Age: the majority of patients are over 65 years of age.
- Heredity: is common in some families but not in others
- Long-term sun exposure
- High blood pressure
- High cholesterol
- Nutritional deficiencies
- Head injury
Symptoms of Macular Degeneration
If the disease progresses to the wet form, patients can begin to perceive straight lines as wavy or crooked, have larger blind spots, and increased central vision loss. With wet macular degeneration, it can take as little as a few days or weeks for central vision loss to progress. Due to these symptoms, many patients require lifestyle changes. Patients can lose the ability to drive, read, or recognize faces. However, peripheral vision remains so patients typically remain capable of being independent.
Diagnosing Macular Degeneration
Our staff also uses an angiography which is the most widely used macular degeneration diagnostic test. During the test, one of our doctors will inject a harmless orange-red dye, Fluorescein, into a vein in the arm. The dye travels through the body to the blood vessels in the retina. A special camera takes multiple photographs. The pictures are then analyzed to identify damage to the lining of the retina or atypical new blood vessels. The formation of new blood vessels from blood vessels in and under the macula is often the first physical sign that macular degeneration may develop. In addition, our staff has invested in an optical coherence tomography scanner which uses light waves to create a contour map of the retina and can show areas of thickening or fluid accumulation.
Macular Degeneration Treatment
Diet and Nutritional Supplements
There has been active research on the use of vitamins and nutritional supplements called antioxidants to try to prevent or slow macular degeneration. Antioxidants are thought to protect against the damaging effects of oxygen-charged molecules called free radicals. A potentially important group of antioxidants are carotenoids. These are the pigments that give fruits and vegetables their color. Two carotenoids that occur naturally in the macula are lutein and zeaxanthin. Some research studies suggest that people who have diets high in lutein and zeaxanthin may have a lower risk of developing macular degeneration. Kale, raw spinach, and collard greens are vegetables with the highest amount of lutein and zeaxanthin. You can also buy nutritional supplements that are high in these and other antioxidants.
Low Vision Aids
Low vision aids may help make it easier to live with the decreased vision of macular degeneration. These aids range from hand-held magnifying glasses to sophisticated systems that use video cameras to enlarge a printed page. Lifestyle aids such as large print books, tape-recorded books or magazines, large print playing cards, talking clocks, and scales and many other devices are available.
Intravitreal Retinal Injections
LUCENTIS and Macugen are new treatments for the wet form of age-related macular degeneration. These injections block abnormal blood vessel growth and leakage.
In rare cases of wet macular degeneration, laser treatment may be recommended. This involves the use of painless laser light to destroy abnormal, leaking blood vessels under the retina. This form of treatment is only possible when the abnormal blood vessels are far enough away from the macula that it will not damage it. Therefore, only rare cases of wet macular degeneration meet these criteria. When laser treatment is possible, it may slow or stop the progression of the disease but is generally not expected to bring back any vision that has already been lost.
Some cases of wet macular degeneration can be treated with photodynamic therapy or PDT. In those cases where PDT is appropriate, slowing of the loss of vision and sometimes, even improvement in vision is possible.