Macular Degeneration

Macular degeneration, often called AMD or ARMD (age-related macular degeneration), is the leading cause of vision loss and blindness in Americans aged 65 and older. AMD occurs with degeneration of the macula, which is the part of the retina responsible for the sharp, central vision needed to read or drive. Because the macula primarily is affected in AMD, central vision loss may occur.

Wet and Dry Forms of Macular Degeneration

Macular degeneration is diagnosed as either dry (non-neovascular) or wet (neovascular). Neovascular refers to growth of new blood vessels in an area, such as the macula, where they are not supposed to be. The dry form is more common than the wet. The wet form of the disease usually leads to more serious vision loss.

 

Dry Macular Degeneration (Non-Neovascular)

Dry AMD is an early stage of the disease and may result from the aging and thinning of macular tissues, depositing of pigment in the macula or a combination of the two processes. Dry macular degeneration is diagnosed when yellowish spots known as drusen begin to accumulate from deposits or debris from deteriorating tissue primarily in the area of the macula. Gradual central vision loss may occur with dry macular degeneration but is not nearly as severe as symptoms associated with the wet form of AMD.

At this time, no FDA-approved treatments are available for the dry form of macular degeneration. However, evidence shows that taking certain nutrients such as beta carotene (vitamin A) and vitamins C and E may help prevent or slow progression of dry macular degeneration. Some eye doctors also recommend that dry AMD patients wear sunglasses with UV protection against potentially harmful effects of the sun.

Wet Macular Degeneration (Neovascular)

In about 10 percent of cases, dry AMD progresses to a more advanced and damaging form of the eye disease known as wet macular degeneration. With wet AMD, new blood vessels grow (neovascularization) beneath the retina and leak blood and fluid. This leakage causes permanent damage to light-sensitive retinal cells, which die off and create blind spots in central vision.

Macular Degeneration Symptoms and Signs

Macular degeneration usually produces a slow, or rarely, sudden painless loss of vision. Early signs of vision loss associated with AMD can include seeing shadowy areas in your central vision or experiencing unusually fuzzy or distorted vision.

An eyecare practitioner often detects early signs of macular degeneration before symptoms occur. Usually this is accomplished through a retinal examination. When macular degeneration is suspected, a brief test using an Amsler grid that measures your central vision may be performed. If the eyecare practitioner detects some defect in your central vision, such as distortion or blurriness, he or she may order a fluorescein angiography to specifically examine the retinal blood vessels surrounding the macula.

Viewing a chart of black lines arranged in a graph pattern (known as an Amsler grid) is one way to tell if you are having these vision problems. Someone with macular degeneration might see some of the lines as wavy or blurred, with some dark areas at the center. See how an Amsler grid works by taking a macular degeneration test.

What Causes Macular Degeneration?

Many forms of macular degeneration may be linked to aging and related deterioration of eye tissue crucial for good vision.

Who Gets Macular Degeneration?

Besides affecting older populations, AMD appears to occur in whites and females in particular. The disease also can result as a side effect of some drugs, and it appears to run in families.

New evidence strongly suggests that smoking is high on the list of risk factors for macular degeneration. Other risk factors for AMD include:

• Having a family member with AMD
• High blood pressure (Hypertension)
• Lighter eye color
• Obesity
• Over-exposure to sunlight
• Drug side effects

 

How Macular Degeneration Is Treated

Treatments for macular degeneration depend on whether the disease is in its early stage or dry form or more advanced, wet form that can lead to serious vision loss. There are no FDA-approved treatments for dry macular degeneration, although nutritional intervention may be valuable in preventing its progression to the more advanced, wet form. Zinc, lutein, zeaxanthin and vitamins A, C and E may help lower the risk for AMD or slow down the progression of dry macular degeneration.

For wet AMD, treatments aimed at stopping abnormal blood vessel growth include FDA-approved drugs of Lucentis, Avastin, Macugen and Visudyne (used with Photodynamic Therapy or PDT).

Although much progress has been made recently in macular degeneration treatment research, complete recovery of vision lost to AMD probably is unlikely. For those who have suffered vision loss, many low vision devices are available to help improve vision by using magnifying lenses and bright lights. Some low vision aids shift images to the periphery for clearer vision.