Age-related macular degeneration (AMD)
Age-related macular degeneration (AMD) is a disease that causes the gradual loss of sight due to blurring or loss of central vision.
Wet macular degeneration is the more advanced type of AMD. It accounts for 90 percent of the severe vision loss caused by macular degeneration.
With this type, the membrane underlying the retina thickens, then breaks. The oxygen supply to the macula is disrupted and the body responds by growing new, abnormal blood vessels. These begin to grow through the breaks of the membrane behind the retina towards the macula, often raising the retina.
To visualize this, imagine the roots of a tree growing and spreading until they crack and grow through a sidewalk. Then imagine rainwater seeping up throughout the cracks. These abnormal blood vessels (the “roots”) tend to be very fragile. They often grow and leak or bleed, causing scarring of the macula. This fluid is called exudate and wet AMD is sometimes called exudative macular degeneration.
This damage to the macula results in rapid central vision loss. Once this vision is destroyed, it cannot be restored. However, there are several treatment options for wet AMD which can be very effective if applied early.
How Did I Get Wet Macular Degeneration?
There are many risk factors that contribute to age-related macular degeneration. Studies in large populations show that statistically a person’s chance of developing a disease is increased by risk factors. In your case, it was probably a combination of things. Some of them are completely out of your control, like family history, gender, ethnicity, and of course, age. Other factors relate to your own lifestyle and can be changed.
How is wet age related macular degeneration diagnosed?
Your doctor will review your medical and family history and conduct a complete eye exam. To confirm a diagnosis of macular degeneration, he or she may do several other tests, including:
Examination of the back of your eye. Your eye doctor will put drops in your eyes to dilate them and use a special instrument to examine the back of your eye. He or she will look for fluid or blood or a mottled appearance that's caused by drusen. People with macular degeneration often have many drusen — yellow deposits that form under the retina.
Test for defects in the center of your vision. During an eye exam, your eye doctor may use an Amsler grid to test for defects in your central vision. If you have macular degeneration, some of the straight lines in the grid will look faded, broken or distorted.
Fluorescein angiography. During this test, your doctor injects a colored dye into a vein in your arm. The dye travels to and highlights the blood vessels in your eye. A special camera takes pictures as the dye travels through the blood vessels. The images will show if you have abnormal blood vessels or retinal changes.
Indocyanine green angiography. Like fluorescein angiography, this test uses an injected dye. It may be used to confirm the findings of a fluorescein angiography or to identify specific types of macular degeneration.
Optical coherence tomography. This noninvasive imaging test displays detailed cross-sections of the retina. It identifies areas of thinning, thickening or swelling. This test is also used to help monitor how the retina responds to macular degeneration treatments.
What Treatments Are Available for Wet Macular Degeneration?
In wet (neovascular/exudative) age-related macular degeneration (AMD), abnormal blood vessels develop under the macula and break, bleed, and leak fluid. This damages the macula and, if left untreated, can result in rapid and severe loss of central vision. The most effective treatments to date for wet AMD are several anti-angiogenic drugs.
Angiogenesis is a term used to describe the growth of new blood vessels and plays a crucial role in the normal development of body organs and tissue. Sometimes, however, excessive and abnormal blood vessel development can occur in diseases such as cancer (tumor growth) and AMD (retinal and macular bleeding).
Substances that stop the growth of these excessive blood vessels are called anti-angiogenic (anti = against; angio = vessel; genic = development), and anti-neovascular (anti = against; neo = new; vascular = blood vessels).
The focus of current anti-angiogenic drug treatments for wet AMD is to reduce the level of a particular protein called vascular endothelial growth factor, or VEGF, that stimulates abnormal blood vessel growth in the retina and macula; thus, these drugs are classified as anti-VEGF treatments.