Macular degeneration, also called age-related macular degeneration (AMD), is a leading cause of vision loss in Americans aged 60 and older. According to the National Eye Institute, AMD affects more than one million Americans, a figure that is expected to more than double by 2050.
What is macular degeneration?
The retina is the light-sensitive tissue that lines the inside of the eye. The retina sends visual images directly to the brain through the optic nerve. The macula is a small area in the center of the retina. It contains an especially high concentration of light sensing cells. The macula is responsible for bringing fine details of objects in the center of vision into sharp focus. AMD occurs due to damage to the macula, resulting in blurred or reduced central vision. The loss of clear, sharp central vision makes activities such as driving, reading, using a computer or watching television more difficult. Because AMD does not affect peripheral vision, it usually does not cause total blindness.
Types of macular degeneration?
There are two main types of AMD:
Dry AMD, the most common type, occurs when the macula becomes thin over time during the aging process. As a result, eyesight in the center of the visual field slowly becomes increasingly blurred.
Wet AMD, the more advanced and harmful form of AMD, occurs when abnormal blood vessels develop behind the macula, causing bleeding, fluid leakage and scarring. Wet AMD can progress from dry AMD or can occur suddenly in people who have not had dry AMD.
Causes of macular degeneration
The exact cause of AMD is not known. Several factors increase the risk of developing AMD, including:
- age older than 50 years
- cardiovascular disease
- family history of AMD
- high blood pressure
- lifestyle smoking
Signs and symptoms of macular degeneration
In the early stages AMD may not cause any signs or symptoms. As the disorder progresses, symptoms may include:
- blind spot in the center of vision
- blurry central vision
- colors that look dull
- difficulty adjusting to changing light levels
- needing brighter light to read or see details
- problems recognizing faces
- seeing straight lines that look curved
How is macular degeneration diagnosed?
To diagnose AMD, an ophthalmologist will perform screening tests that may include:
Amsler grid test to check for visual distortions or blind spots comprehensive dilated eye examination, in which special drops are used to dilate the pupils, followed by a close inspection of the interior of the eye. One early sign of AMD this test can detect is the presence of drusen, tiny white or yellow deposits that form beneath the retina.
Visual acuity test, a letter chart that checks the sharpness of vision at various distances Additional tests to confirm an AMD diagnosis or monitor AMD progression include: fundus fluorescein angiography, an imaging technique used to examine blood vessels and other structures at the back of the eye optical coherence tomography, a non-invasive imaging technique that captures high resolution cross-section images of the layers within the retina
Treatments for macular degeneration
Treatment for AMD depends on the type and stage.
Options may include:
- Dietary supplements. According to the Centers for Disease Control and Prevention (CDC), daily consumption of certain vitamins and minerals may help keep AMD from getting worse. Green, leafy vegetables are excellent sources of beta-carotene, copper, vitamin C, vitamin E and zinc.
- Medications. Anti-angiogenic drugs or injections of anti-VEGF (vascular endothelial growth factor) drugs help slow or stop the growth of abnormal blood vessels in the retina. Photodynamic therapy. This procedure combines photosensitive drugs with laser treatment to seal off abnormal blood vessels.