What is macular degeneration?
Although macular degeneration reduces vision in the central part of the retina, it does not affect the eye's side, or peripheral, vision. For example, you could see the outline of a clock but not be able to tell what time it is. Macular degeneration is the leading cause of severe vison loss in Caucasians over 65 years of age.
If you notice words looking blurry on a page, a dark or empty area in the center of your vision, or crookedness of straight lines, you may have smptoms of macular degeneration. You may lose vision in one eye but be able to see well out of the other eye. You will notice central vision problems more quickly if both eyes have macular degeneration.
Macular degeneration alone does not result in total blindness. People continue to have some useful vision and are able to take care of themselves.
What causes macular degneration?
Many older people develop macular degeneration as part of the body's natural aging process. It can be hereditary and can be caused by certain medical conditions.
The two most common types of age-related macular degeneration are "dry" (atrophic) and "wet" (exudative):
"Dry" macular degeneration (atrophic)
Most people with macular degeneration have the "dry" type. It is caused by aging and thinning of the tissues of the macula. Vision loss is usually gradual.
"Wet" macular degeneration (exudative)
"Wet" macular degeneration accounts for about 10% of all cases. It results when abnormal blood vessels form at the back of the eye. These new blood vessels leak fluid or blood and blur central vision. Vision loss may be rapid and severe.
Certain types of "wet" macular degeneration can be treated with laser surgery, a brief outpatient procedure that uses a focused beam of light to slow or stop leaking blood vessles that damage the macula. A treatment called photodynamic therapy (PDT) uses a combination of a special drug and laser traetment to slow or stop leaking blood vessels.
Another form of treatment targets a specific chemical in your body that is critical in causing abnormal blood vessels to grow under the retina. That chemical is called vascular endothelial growth factor (VEGF). Anti-VEGF drugs block the trouble-causing VEGF, reducing the growth of abnormal blood vessels and slowing their leakage.
These procedures may preserve more sight overall, though they are not cures that restore vision to normal. Despite advanced medical treatment, most people with macular degeneration still experience some vision loss.
What are the symptoms of macular degeneration?
Macular degeneration can cause different symptoms in different people. The condition may be hardly noticeable in its early stages. Sometimes only one eye loses vision while the other eye continues to see well for many years.
Deposits under the retina called drusen are a common feature of macular degeneration. Drusen alone usually do not cause vision loss, but when they increase in size or number, this generally indicates an increased risk of developing advanced age-related macular degeneration (AMD). People at risk for developing advanced AMD have significant drusen, prominent dry AMD, or abnormal blood vessels under the macula in one eye ("wet" form).
But when both eyes are affected, the loss of central vision may be noticed more quickly.
How is macular degeneration diagnosed?
Many people do not realize that they have a macular problem until blurred vision becomes obvious. Our doctor can detect early stages of macular degeneration during a medical eye examination, which is a dilated exam and may include the following:
- Viewing the macular with an opthalmoscope
- Retinal photograph
- Visual fields test
- OCT test
Sometimes special photographs, called angiograms, are taken to find abnormal blood vessels under the retina. Fluorescent dye is injected into your arm and your eye is photographed as the dye passes through the blood vessels in the back of the eye.
How is macular degeneration treated?
Despite ongoing medical research, there is no cure yet for "dry" macular degeneration. Nutritional supplements may slow macular degeneration. Treatment of this condition focuses on helping a person find ways to cope with visual impairment, and sometimes taking nutritional supplements suggested by your eye doctor.
"Wet" macular degeneration may be treatable by a variety of methods depending on the particular findings in a given patient. The methods include laser treatment of retinal blood vessel leaks, laser treatment enhanced with intravenous dyes (PDT), thermal treatment (TTT), and injection of chemicals to retard blood vessel growht. Patients may be offered enrollment in treatment studies that are in process.
Despite advanced medical treatment, many people with macular degeneration still experience some vision loss.