What is Macular Degeneration?

Macular degeneration, also known as age-related macular degeneration, AMD, or ARMD, occurs when the central portion of your retina, the macula, wears down, resulting in vision loss. 

Your macula is responsible for focusing central vision in the eye. It controls your ability to read, drive, recognize faces and colors, and see objects in refined detail.

When the cells of your macula deteriorate, you begin to lose central vision, but retain peripheral vision. The prevalence and severity of AMD increases with age. 

Macular degeneration is one of the leading causes of vision loss. It affects over 10 million Americans. It is most present in Caucasians. 

Types of Macular Degeneration

There are two types of macular degeneration: dry (non-exudative) and wet (exudative). The majority of cases, 80 to 90 percent, of all AMD are the dry form.

Dry Macular Degeneration

People who have dry AMD will develop yellow deposits, called drusen, in their macula. At first, a few small drusen may not affect your vision. However, as they increase in size and number, they may cause visual distortion or dimness, especially while reading.

As the eye disease progresses, the light-sensitive cells in your macula wear away and eventually die. This can cause blind spots in the center of your vision and may ultimately result in the loss of central vision. 

Wet Macular Degeneration

In wet AMD, the blood vessels underneath your macula begin to leak blood and other fluids into the back of the eye. This distorts your vision and causes straight lines to appear wavy. 

Eventually, these abnormal blood vessels and their fluids will form scars, resulting in a permanent central vision loss. Wet AMD often results in more severe vision loss than dry cases.

Stargardt Disease

In rare cases, approximately 1 in 20,000, AMD will develop in children or teenagers. This is known as Stargardt disease. While Stargardt disease is similar to AMD, it is thought to be caused entirely by genetics.

Stages of Macular Degeneration

There are three stages of macular degeneration:

• Early AMD. Most people do not experience vision loss in the early stage. An eye doctor can diagnose early AMD during an eye exam by spotting medium-sized drusen (yellow deposits) in the macula. 
• Intermediate AMD. In this stage, there is usually some vision change or loss. However, not everyone will experience vision problems yet. Optometrists will perform an eye examination to look for larger drusen or pigment changes in the retina.
• Late AMD. During late AMD, vision loss has become noticeable. There may be permanent thinning or scarring of cells. 

Symptoms of Macular Degeneration

In the early stages of AMD, you may not recognize any symptoms. They often go unnoticed until both eyes are affected, or your eyesight deteriorates significantly.

Signs of AMD include:

• Need for brighter lighting to read
• Blurriness of printed words
• Straight lines appearing bent or wavy
• Dark or blurry areas in the center of your vision
• Difficulty recognizing faces
• Reduced brightness or intensity of colors

When to See a Doctor

If you experience any of these symptoms, you should schedule an eye exam immediately. You should also undergo an annual eye examination, especially after the age of 50, to maintain proper eye health care.

Causes of Macular Degeneration

AMD is a little-understood disease. The exact cause of macular degeneration is still unknown. Researchers believe there are genetic components as well as environmental factors that may affect your susceptibility to AMD.  

AMD Risk Factors

• Age. The most prominent risk factor is aging. Most cases of AMD occur in people over the age of 50. 
• Family history. Researchers have identified certain genes that are related to the development of AMD.
• Race. Caucasians have a higher risk of AMD. 
• Smoking. Smoking, or being exposed to second-hand smoke, increases your chances of developing AMD.
• Unhealthy Diet. Research suggests that obesity and unhealthy diets may increase the severity of AMD.
• Cardiovascular disease. You may be more likely to develop the wet form of macular degeneration if you have conditions that affect your heart or blood vessels, such as high blood pressure.

How is AMD Diagnosed?

AMD is diagnosed during a complete eye examination. If you are at risk for AMD, they may perform one or more tests to check for signs of macular degeneration:

Amsler grid. Your optometrist may ask you to look at an Amsler grid. This will test for deficiencies in your central vision. If some of the straight lines in the grid appear wavy, broken, or faded, this may be a sign of macular degeneration.

Retinal Examination. Your eye doctor may dilate your eyes by administering eye drops. They will then use a special instrument to examine the back of your eye. They will be looking for drusen, the yellow deposits that form under the retina. These are a sign of macular degeneration. 

Fluorescein angiography. This involves your doctor injecting a colored dye into your arm. The dye travels to the blood vessels in your eye. A camera will take several pictures as the dye highlights the blood vessels. The images will reveal if you have abnormal blood vessels or changes in your retina.

Optical coherence tomography. This is a non-invasive imaging procedure that will take detailed cross-sectional images of your retina. It will identify areas of retinal thinning, thickening, or swelling. 

Prevention

While doctors are not one hundred percent certain of AMD's causes, there are certain preventative measures you can take to decrease the risk of developing severe macular degeneration in the future, including:

• Manage other medical conditions. See your doctor and follow their treatment regimen for any other medical condition, especially cardiovascular diseases.
• Don’t smoke. Smoking increases your chances of AMD significantly.
• Eat a healthy diet. A balanced diet filled with antioxidants and omega-3 fatty acids may reduce your risk of developing AMD.
• Maintain a healthy weight. Exercise regularly and maintain a proper diet. Obesity is a risk factor for AMD.

Macular Degeneration Treatment Options

There is no known cure for macular degeneration. For dry AMD, there are no FDA approved treatment methods. However, there are many treatment options depending on the type and severity of your condition.

Nutritional Therapy

The Age-Related Eye Disease Study (AREDS) by the National Eye Institute, has found that, in clinical trials, nutritional supplements have benefited people with intermediate or late AMD. 

The original AREDS formula contains:

The AREDS2 formula was modified to remove beta-carotene, which increased smokers’ chances of lung cancer:

The vitamins C and E, beta-carotene, zinc, copper, lutein, zeaxanthin, and omega-3 fatty acids have all been linked to reducing the risk of vision loss.

Your doctor may prescribe you nutritional supplements containing antioxidant vitamins to combat the progression of AMD.  

Photodynamic Therapy

Laser therapy can reduce the progression of wet AMD. In this treatment, an ophthalmologist injects a dye to guide the laser to the affected areas. The procedure seals off leaking blood vessels and leaves healthy ones alone. 

However, laser therapy has not proven successful long-term, and this procedure will likely need to be repeated. 

Anti-VEGF Therapy

Anti-VEGF drugs are currently the most common and effective treatment for AMD. VEGF stands for vascular endothelial growth factor. This drug is injected into the eye and stimulates the growth of new blood vessels. 

This procedure takes approximately fifteen minutes and has shown great potential in slowing down and even preventing macular degeneration progression. 

Low-Vision Aids

Low-vision devices improve vision for people who suffer from poor vision. They can be optical, non-optical, or electronic. There are a wide variety of instruments and techniques available.