How Is Age-Related Macular Degeneration Diagnosed?
Age-related macular degeneration can be detected in a routine eye exam. One of the most common early signs of macular degeneration is the presence of drusen -- tiny yellow deposits under the retina. Your doctor can see these when examining your eyes. Your doctor may also ask you to look at an Amsler grid -- a pattern of straight lines that resemble a checkerboard. Some of the straight lines may appear wavy to you, or you may notice that some of the lines are missing. These can be signs of macular degeneration.
If your doctor detects age-related macular degeneration, you may have a special photograph called an OCT or a procedure called fluorescein angiography or both. The OCT shows a magnified 3D image of your retina. With the angiography procedure, a dye is injected into a vein in the arm. Photographs are taken as the dye reaches the eye and flows through the blood vessels of the retina. If there are new vessels or vessels leaking fluid or blood in the macula, the photographs will show their exact location and type.
Age-related macular degeneration (AMD) is the foremost cause of vision loss in the U.S., with millions of Americans showing some sign of the disorder. AMD is uncommon in people younger than 55. If you are over 65, macular degeneration may already affect your central vision -- the vision you need for driving as well as close work like reading and sewing.
AMD occurs in two forms:
Dry: Most common
Wet: Less common, but requires immediate medical attention to preserve central vision
Early detection of age-related macular degeneration is very important because there are treatments that can delay or reduce the severity of the disease.
Tests for Age-Related Macular Degeneration
Initial tests for age-related macular degeneration include measurement of your visual acuity and a dilated exam of the retina. While studying the retina, the ophthalmologist looks for specific signs of macular degeneration.
If signs of age-related macular degeneration are found, the ophthalmologist will often take detailed pictures of the retina for future comparison. Tests may also include:
Angiography: As mentioned above, In this procedure, a dye is injected into a vein in the arm. The test identifies vessels which cannot be seen with the naked eye and which may need to be treated with the laser or photocoagulation.
Optical coherence tomography (OCT): This is a noninvasive exam that produces a cross-sectional image of the retina. This method is helpful in identifying how much the retinal layers are distorted and whether swelling is increasing or decreasing following treatment with injections or laser.