Age-related Macular Degeneration (AMD)

AMD or Age-related Macular Degeneration is an unfortunately quite common eye disease that develops with aging. Age-related macular degeneration gradually destroys sharp, central vision.

That is very discomforting, as central vision is needed for seeing objects clearly and for allmost all daily tasks like i.e. reading and driving. Some people are lucky, with them AMD develops very slowly and has little effect on their vision as they age. But in others, this eye disease advances faster and can lead to a loss of vision in one or even both of their eyes.

AMD damages the vision

First let's look what the retina and the macula exactly is: The retina is a very tissue (same as a sheet of paper). It lines the back of the eye and sends the visual signals through nerves to the brain. In the center of the retina is a very small spot called the macula. The macula is composed of many millions of light-sensing nerve cells that help to produce the central vision.

AMD occurs in two forms:

• Dry AMD : 90% of people with Age-related Macular Degeneration suffer from this type of AMD. Ther is no scientifc explanation what causes dry AMD. Some studies suggest that a part of the retina becomes diseased, which in turn may lead to a slow breakdown of the light-sensing nerve cells in the macula and consequently will lead to a gradual loss of the central vision.
• Wet AMD : Wet Age-related Macular Degeneration is the much more serious problem. Only about 10 percent of the patients with AMD suffer from wet AMD. But it is responsible for 90 percent of all blindness that can develop from AMD. Wet AMD develops from a dry AMD that develops into a more serious illness: As dry AMD gets worse, new blood vessels can begin to grow and cause wet AMD. The new blood vessels often are very fragile and they allmost allways start to leak blood and fluid under the macula. These additional fluids cause very fast progressing damage to the macula. As the damage grows, it can lead in a very short period of time to the loss of central vision.

The risk factors for Age-related Macular Degeneration

The most important risk factor for age-related macular degenration is age.

It is possible but unusual for AMD to occur during middle age. Scientific studies show that people over the age of 60 are by far at a greater risk than any other age group. Just two examples from a large study: The risk for AMD for a middle aged person is only 2 percent, whilst for a person over the age of 75 years there is a chance of approx. 30 persent to suffer from AMD.

Other AMD risk factors include:

• Gender : Women seem to be at greater risk for Age-related Macular Degeneration than men.
• Race : Whites are much more likely to lose vision from AMD than Blacks.
• Smoking : Smoking most likely increase the risk of developing AMD.
• Family History : If you have an immediate family members who allready has AMD you are at a higher risk of also developing AMD.

The symptoms for Age-related Macular Degeneration

Age-related Macular Degeneration is difficult to detect, because both dry AMD and wet AMD cause no pain. Early signs of dry AMD is blurred vision due to the degeneration of individula macula cells. As fewer cells in the macula are functioning, people see details less clearly, faces or words in a book start to blur. Often this blurred vision will be reduced or go away in brighter, better light. Once the loss of these light sensing cells becomes more important, people may notice a small, and over time growing blind spot in the center of their field of vision.

The classic early symptom of wet AMD is that straight lines are seen as bent lines. This is the result of the fluids from the leaking vessels is accumulated and then lifts the macula. The result is this distorted vision. A small blind spot is also likely to develop in wet AMD, resulting in the same loss of the central vision as explained for dry AMD.

How is it detected? Your eye care professional may suspect AMD if you are over age 60 and have had recent changes in your central vision. To look for signs of the disease, he or she will use eye drops to dilate, or enlarge, your pupils. Dilating the pupils allows your eye care professional to view the back of the eye better. You may also be asked to view an Amsler grid, a pattern that looks like a checkerboard. Early changes in your central vision will cause the grid to appear distorted, a sign of AMD. How can it be treated? No treatment now exists for dry AMD. It has been suggested that taking certain extra vitamins and minerals may slow the progress of the disease. But this treatment needs much more research before scientists can know for sure if it's helpful. Do NOT depend on the grid displayed below for any diagnoses. While covering one eye, look at dot in center of grid. If lines around dot are wavy or distorted, you should see your eye care professional.

Eye care professionals can treat some cases of wet AMD with laser surgery. This treatment involves aiming a strong light beam onto the new blood vessels to destroy them. Laser surgery is done in a doctor's office or in an eye clinic and lasts a short period of time. Although a person may go home the same day, he or she will need to return for follow-up exams.

What research is being done? The National Eye Institute is funding a number of research studies to learn what causes AMD and how it can be better treated. For instance, in the Age-Related Eye Diseases Study (AREDS), researchers are assessing the aging process in the eyes of thousands of older people to discover the earliest signs of AMD. The same study is also evaluating the effects of certain vitamins and minerals in preventing or slowing the progress of AMD.

At the same time, other scientists are trying to learn more about how the cells in the retina work. This knowledge will allow them some day to pinpoint the cause of the disease and design methods to prevent it. What can you do to protect your vision? Although there is no effective treatment for dry AMD at this time, it is crucial that those who progress to wet AMD and need laser surgery have it before the disease destroys central vision. For this reason, if you have dry AMD or are age 60 or older, you should have your eyes examined through dilated pupils at least once a year. You may also want to get an Amsler grid from your eye care professional to check your vision at home.