Macular degeneration is the leading cause of severe vision loss in people over age 60. It occurs when the small central portion of the retina, known as the macula, deteriorates. The retina is the light-sensing nerve tissue at the back of the eye.

The macula contains the greatest concentration of cones; the light receptors that make detailed vision and color vision possible. If the macula deteriorates, the affected eye will be unable to perceive detail, such as print on a page, or to see the world in vivid color.

Because the disease develops as a person ages, it is often referred to as age-related macular degeneration (AMD). Progressive macular degeneration often results in a complete loss of central vision, but it does not lead to total blindness since the peripheral (side) vision is unaffected.

Types and Causes

The Dry Form: The dry form is the most common type of macular degeneration. In theses cases, the delicate tissues of the macula break down and atrophy

The Wet Form: The wet form of macular degeneration while not as common, can potentially be more damaging. It is caused by the growth of abnormal blood vessels behind the macula. These abnormal blood vessels leak fluid and ultimately form scar tissue. Sometimes, the dry form of macular degeneration can turn into the wet form.

Common Symptoms and Diagnosis

In early dry AMD people often are relatively asymptomatic. As the disease progresses one or more of the following may occur:

• A loss of ability to see objects clearly

• Distorted vision -straight lines appear crooked-

• A loss of clear color vision

• A dark or empty area appears in the center of the vision

People who think they may have a macular problem need to see an ophthalmologist for a thorough retinal examination.

Treating Macular Degeneration

There is as yet no outright cure for macular degeneration, but some treatments may delay its progression or even improve vision.

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. (See Nutrition and Macular Degeneration below)

For wet AMD, laser treatments to destroy abnormal, leaking blood vessels is sometimes effective. Other drugs such as Macugen and Visudyne, which aim at stopping abnormal blood vessel growth, can be combined with laser treatment (Photodynamic Therapy or PDT). Some new treatments such as Lucentis and Avastin are showing promise for possibly even reducing vision loss in a significant number of macular degeneration patients.

Nutrition and Macular Degeneration

Many researchers and eye care practitioners believe that certain nutrients — zinc, lutein, zeaxanthin and vitamins A, C and E — help lower the risk for AMD or slow down the progression of dry macular degeneration. Benefits of high levels of antioxidants and zinc for halting or slowing development of macular degeneration have been widely reported based on results released in 2001 from the Age-Related Eye Disease Study (AREDS) conducted by the National Eye Institute.

Preventative Measures

Although there is no cure for macular degeneration, people can try to reduce their chance of developing this problem by altering their lifestyle. Research into this area indicates that the following measures may help:

• Eating a balanced diet, which is rich in leafy green vegetables such as spinach.

• Wearing sunglasses, which block ultraviolet light.

• Following a regular exercise program.

• Eating foods low in fat and cholesterol.

• Quitting smoking.