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 procedure called angiography. In this procedure, a dye, such as fluorescein or indocyanine green, 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.
Macular degeneration is the leading cause of severe vision loss in people over age 60. It occurs when the small central portion of the retina, known as the macula, deteriorates. The retina is the light-sensing nerve tissue at the back of the eye. Because the disease develops as a person ages, it is often referred to as age-related macular degeneration (AMD). Although macular degeneration is almost never a totally blinding condition, it can be a source of significant visual disability.
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): 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.
Microperimetry using the Rodenstock scanning laser ophthalmoscope: This is used to quantify macular sensitivity and fixation pattern.