Age-related macular degeneration (AMD) 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 (i.e. thread a needle, read small print, and read street signs.)
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.
Causes of macular degeneration include the formation of deposits called drusen under the retina, and in some cases, the growth of abnormal blood vessels under the retina. With or without treatment, macular degeneration alone almost never causes total blindness.
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 ophthalmologist right away, as the dry form can change into the more damaging form of macular degeneration called wet (exudative) macular degeneration. While there is no medication or treatment for dry macular degeneration, some people may benefit from a vitamin therapy regimen for dry macular degeneration.
Using an Amsler grid to test for macular degeneration
To use the Amsler grid, wear your reading glasses and hold the grid 12 to 15 inches away from your face in
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
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.
About 10 percent of people who have macular degeneration have the wet form, which can cause more damage to your central or detail vision than the dry form.
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 that from dry macular degeneration.
SOURCE American Academy of Ophthalmology – eyeSmart