Age-related macular degeneration (ARMD) is a deterioration or breakdown of the eye's macula. The macula is a small area in the retina — the light-sensitive tissue lining the back of the eye. The macula is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly. The macula allows you to thread a needle, read small print, and read street signs. The peripheral retina is responsible for side (or peripheral) vision. If someone is standing off to one side of your vision, your peripheral retina helps you know that person is there by allowing you to see their general shape.
Many older people develop macular degeneration as part of the body's natural aging process. There are different kinds of macular problems, but the most common is age-related macular degeneration.
With macular degeneration, you may have symptoms such as blurriness, dark areas or distortion in your central vision, and perhaps permanent loss of your central vision. It usually does not affect your side, or peripheral vision. For example, with advanced macular degeneration, you could see the outline of a clock, yet may not be able to see the hands of the clock to tell what time it is.
Findings of macular degeneration include deposits called drusen under the retina, atrophy or degeneration of retinal cells, and in some cases, the growth of abnormal blood vessels under the retina. People with more advanced cases of macular degeneration may continue to have useful vision using their side, or peripheral vision.
When macular degeneration does lead to loss of vision, it usually begins in just one eye, though it may affect the other eye later.
Types of macular degeneration:
Dry Macular Degeneration
Dry macular degeneration is condition caused by aging and thinning (atrophy) of the tissues of the macula. Macular degeneration usually begins when tiny yellow or white deposits of fatty protein called drusen form under the retina. Eventually, the macula may become thinner and stop working properly.
With dry macular degeneration, vision loss is usually gradual. People who develop dry macular degeneration must carefully and constantly monitor their central vision. If you notice any changes in your vision, you should tell your doctor right away, as the dry form can progress into the more damaging form of macular degeneration called wet macular degeneration. While there is no medication or treatment for dry macular degeneration. Your doctor will likely advise vitamin therapy, smoking cessation, and dietary modifications.
Wet macular degeneration (also called Neovascular Macular Degeneration)
Wet macular degeneration occurs when abnormal blood vessels begin to grow underneath the retina. This blood vessel growth is called choroidal neovascularization (CNV) because these vessels grow from the layer under the retina called the choroid. These new blood vessels may leak fluid or blood, blurring or distorting central vision. Vision loss from this form of macular degeneration may be faster and more noticeable than dry macular degeneration.
The longer these abnormal vessels leak or grow, the more risk you have of losing more of your detailed vision. Also, if abnormal blood vessel growth happens in one eye, there is a risk that it will occur in the other eye. The earlier that wet macular degeneration is diagnosed and treated, the better chance you have of preserving some or much of your central vision. That is why it is so important that you and your ophthalmologist monitor your vision in each eye carefully.
Using an Amsler grid to test for Macular Degeneration
If you have been diagnosed with macular degeneration, you should use a chart called an Amsler grid every day to monitor your vision, as dry macular degeneration can change into the more damaging wet form.
To use the Amsler grid, wear your reading glasses and hold the grid 12 to 15 inches away from your face in good light.
Cover one eye.
Look directly at the center dot with the uncovered eye and keep your eye focused on it.
While looking directly at the center dot, note whether all lines of the grid are straight or if any areas are distorted, blurry or dark.
Repeat this procedure with the other eye.
If any area of the grid looks wavy, blurred or dark, contact your ophthalmologist.
If you detect any changes when looking at the grid, you should notify your ophthalmologist immediately.