Macular degeneration is a disease of the macula - a small area in the retina at the back of the eye. The macula allows you to see fine details and do things sauch as read and drive. When the macula does not work properly, your central vision an be blurry and hace areas that are dark or distorted. Macular degeneration affects your ability to see near and far, and can make some activities - like threading a needle or reading- difficult or impossible.
Macular degeneration is the most common cause of severe vision loss in people older than 50. Although macular degeneration reduces vision in the central part of the retina, it usually does not affect the eye's side (peripheral) vision. For example, you may be able to see the outline of the a clock but not be able to tell what time it is. Macular degeneration alone usually does not cause total blindness. Even in the more advanced cases, people usually continue to have some useful vision and are often able to take care of themselves. In some cases, macuar degeneration may not affect your vision very much in other cases, however, vision loss may be more rapid and severe.
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 (AMD or ARMD).
Our bodies constantly react with the oxygen in our environment. Over time, as a result of this activity, our bodies produce free radicals. These free radicals affect our cells, sometimes damaging them. This is called oxidative stress, and it thought to play a major role in how AMD develops. Many people (approximately 1 in 3 Caucasians) have genetic changes that make them more prone to this damage.
Major risk factors for AMD are:
- Being more than 50 years old
- Having a family history of AMD
- Cigarette smoking
Another risk factor for developing AMD may include having abnormal cholesterol levels.
Many people with AMD have deposits under the retina called drusen. Drusen alone usually do not cause vision loss, but when they grow in size or number, there is an increased risk of developing advanced AMD.
The two types of AMD are dry and wet.
Ninety percent of people with AMD have the "dry" form. This condition is caused by damage (oxidative stress) and results in thinning of the macular tissue. Vision loss is usually gradual. Many people with this form also have difficulty adjusting to changes inlight. For example, they may find it takes them some time to adjust to seeing indoors when they come in from outdoors.
Ten percent of people who have AMD have the "wet" form. Many of these people develop significant vision loss. Wet AMD results when abnormal blood vessels form underneath the retina. These new blood vessels leak fluid or blood and blur central vision. Vision loss may be rapid and severe.
Macualr degeneration can cause different symptoms in different people. Some people hardly notice AMD in its early stages. Sometimes only one eye loses vision while the other eye continues to see well for many years. But when both eyes are affected, you notice the loss of central vision quickly.
Usually, you will notice vision loss when you find:
- Words on a page look blurred
- A dark or empty area appears in the center of vision
- Straight lines look distorted
Many people do not relize that they have a macular problem until blurred vision becomes obvious. Your ophthamologist can detect early stages of AMD during a medical eye examination.
Antioxidant vitamins and zinc may reduce the impact of AMD in some people. A large study found that people at risk for AMD lowered their risk by 25% when treated with a high dose combination of Vitamin C, Vitamin E, Beta Carotene, Zinc and Copper.
Another large study in women showed a benefit from taking folic acid and vitamins B6 and B12. And a large study evaluating the benefits of lutein and fush oil is ongoing.
Among those who either have no AMD or very early AMD, taking supplements do not appear to be beneficial. Family members of patients with AMD should check with their doctor before taking these vitamins. It is very important to remember that vitamin supplements are not a cure for AMD, nore will they give you back your lost vision. In certain case, there may be some risks with taking supplements. However, specific amounts of these supplements do play a key role in helping some people at risk for advanced AMD to maintain their vision.
The most common treatment for wet AMD involves injecting a drug into the eye that stops blood vessel growth and bleeding. These drugs, known as VEGF blockers or anti-VEGF treatments, target a specific chemical in your body that causes abnormal blood vessel growth under the retina. That chemical is called vascular endothelial growth factor (VEGF). These anti-VEGF treatments improve vision in some people with wet AMD.
One symptom of macular degeneration is dark areas in your central vision.
Click on grid to be taken to a video of how to use the Amsler Grid to test your vision.