What is AMD?
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.  It is your macula that allows you to recognize the details of the person’s face.

With AMD, you may have 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. When AMD does lead to loss of vision, it usually begins in just one eye, though it may affect the other eye later.  Many people are not aware that they have macular degeneration until they have a noticeable vision problem or until it is detected during an eye examination.

There are two types of AMD:

Dry, or atrophic, AMD (also called non-neovascular AMD)
Most people who have AMD have the dry form. This condition is caused by aging and thinning of the tissues of the macula. Macular degeneration usually begins when tiny yellow or white pieces of fatty protein form under the retina. These deposits are called drusen. Eventually, the macula may become thinner and stop working properly. With dry AMD, vision loss is usually gradual. The dry form can change into the more damaging form of AMD called wet (exudative) AMD.

Wet, or exudative, AMD (also called neovascular AMD)
The wet form of macular degeneration occurs in about 10 percent of all macular degeneration cases, but it can cause more damage to your central or detail vision than the dry form.  Wet AMD occurs when abnormal blood vessels begin to grow underneath the retina. These new blood vessels may leak fluid or blood, blurring or distorting central vision. Vision loss from this form of AMD may be faster and more noticeable than that from dry AMD.

Who is at risk for AMD?
Many older people develop macular degeneration as part of the body’s natural aging process. Major risk factors for AMD are:

• Being older than 50 years old
• Having a family history of AMD
• Cigarette smoking
• High cholesterol levels
• High blood pressure

How is AMD diagnosed?
Many people do not realize they have a macular problem until they notice they have blurred or distorted vision. Regular eye examinations by an ophthalmologist may help to detect problems before you are even aware of them. Your ophthalmologist can see early stages of AMD during a comprehensive eye examination.

The American Academy of Ophthalmology recommends that adults with no signs or risk factors for eye disease get a baseline eye disease screening at age 40 — the time when early signs of disease and changes in vision may start to occur. Based on the results of the initial screening, an ophthalmologist will prescribe the necessary intervals for follow-up exams.

To check for macular degeneration, your eye doctor will dilate your pupils using eyedrops and examine your eyes with an ophthalmoscope, a device that allows him or her to see the retina and other areas at the back of the eye. If AMD is detected, your doctor may have you use an Amsler grid to check for wavy, blurry or dark areas in your vision.

Fluorescein angiography
These are photographs to determine if abnormal blood vessels are under the retina.  To do this test, fluorescein dye is injected into a vein in your arm. The dye travels throughout the body, including your eyes. Photographs are taken of your eye as the dye passes through the retinal blood vessels. Abnormal areas will be highlighted by the dye, indicating to your doctor whether treatment is possible. If treatment options are available, these photographs will provide your doctor with a map to guide the treatment.

Optical Coherence Tomagraphy or OCT

This machine allows visualization of retina in very fine anatomic details, showing damages and swelling of the retina in case of AMD. 

How is AMD treated?
Unfortunately, at this time there is no single proven treatment for the dry form of AMD. However, the Age-Related Eye Disease Study (AREDS) has shown that antioxidant vitamins and zinc may reduce the impact of AMD in some people by slowing its progression toward more advanced stages.  The AREDS nutrient supplementation shown to be beneficial includes:

• Vitamin C – 500 mg
• Vitamin E – 400 IU
• Beta carotene – 15 mg (25,000 IU)
• Zinc oxide – 80 mg
• Copper (as cupric oxide) – 2 mg (to prevent copper deficiency, which may be associated with taking high amounts of zinc)

Another large study in women showed a benefit from taking folic acid and vitamins B6 and B12. And a large study evaluating the possible benefits of lutein and fish oil (omega-3) is ongoing.

These vitamins and minerals are recommended in specific daily amounts in addition to a healthy, balanced diet. Some people may not wish to take large doses of antioxidants or zinc because of medical reasons. Beta carotene has been shown to increase the risk of lung cancer in smokers or recent past smokers, so this supplement should not be used by people who currently smoke or recently quit smoking.

It is very important to remember that vitamin supplements are not a cure for AMD, nor will they give you back vision that you may have already lost from the disease.

Treating wet AMD
Anti-VEGF treatment
The medication is administered directly to the eye and reduces the growth of abnormal blood vessels, slows their leakage, helps to slow vision loss, and in some cases improves vision.

Thermal laser treatment

The laser beam in this procedure is a high-energy, focused beam of light that produces a small burn when it hits the area of the retina to be treated. This destroys the abnormal blood vessels, preventing further leakage, bleeding and growth.

Photodynamic therapy (PDT)
This therapeutic procedure uses a combination of a light-activated drug called a photosensitizer and a special low-power, or cool, laser to treat wet AMD right at the center of the macula.

What happens when AMD cannot be treated?
If you have untreatable AMD, you can make the most of your remaining vision by learning to “see again” with the vision you do have and with the help of special low-vision rehabilitation, devices and services.  People with low vision can learn new strategies to accomplish daily activities. These skills, including mastering new techniques and devices, help people with advanced AMD regain their confidence and live independently despite loss of central vision.

While there is little that can be done to improve the eyesight of someone who has AMD, with early detection, the rate of vision loss can be slowed. The keys to slowing vision loss are to understand your condition and work closely with your ophthalmologist to monitor your vision. Even with macular degeneration, you can still maintain an enjoyable lifestyle.

For more information, please visit
http://www.geteyesmart.org/eyesmart/diseases/amd.cfm