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Hope & Research

What is Macular Degeneration?

Age-related macular degeneration (AMD) affects the eyesight of 13 million Americans. In many cases, the onset of AMD drastically limits one's mobility and devastates one's sense of independence and security.l It strikes painlessly, disrupting the central vision needed to read and to write, to drive and to watch TV.

AMD most often affects persons in their late fifties or sixties just when they are preparing to enjoy their leisure years. It is ironic that medical progress in combating fatal diseases has extended the life span of millions who may then fall prey to AMD and other age-related diseases. An estimated 200,000 Americans develop a severe form of AMD each year, making it the leading cause of functional blindness in people 65 or older. One-third of the population over age 75 is likely to develop AMD.

At present, there is no known cure or lasting treatment for AMD, and until recently, it had been considered impossible to treat in any form. However, new advances in eye research such as injection with Avastin or Lucentis offer hope to those whose lives have been affected by this disease or in whom the disease is likely to develop.

Technically, AMD is a group of similar diseases that destabilize the macula, a tiny section of the retina in back of the eye. The retina is a paper thin tissue that receives images and converts them into electrical signals sent to the brain through the optic nerve. The retina contains two forms of light-receiving cells called rods and cones. The macula, which is about the size of a pinhead, is rich in cone cells which give us our color and central vision. Rod cells help us to see at night.

There are two main types of macular degeneration--the "dry" type and the "wet" type. In either case, the disease leaves peripheral vision intact and most of those afflicted retain some usable sight.'

The "dry" (or atrophic) form accounts for 9 out of 10 AMD cases. It is usually slow to develop and does not cause total loss of central vision. Dry AMD is characterized by a thinning or deterioration of tissue underneath the macula and a slow breakdown of the cone cells.

The "wet" (or exudative) form occurs in only 10 percent of AMD patients, but it causes about 90 percent of the cases of severe visual loss due to the disease. In "wet" AMD, abnormal blood vessels develop rapidly under the retina and leak blood or fluid that damage the macula causing severe and sometimes sudden vision loss. The wet form often results in the growth of dense scar tissue.

The exact cause of AMD is unknown, but there is a significant genetic component in the majority of patients. It also has a higher incidence with greater age and in women than in in men. Smoking worsens AMD. The condition is more prevalent among Caucasians than among African-Americans, and it appears to be most common in people with blue or light-colored eyes. Another risk factor is excessive exposure to ultraviolet (UV) rays, especially from the sun.

Anyone over 50, especially those with a family history of AMD, should have their eyes examined regularly by their ophthalmologist (eye MD).

AMD is usually painless. The "dry" type can be very slow in forming, but the "wet" type is likely to develop quickly and may cause sudden visual loss or distortion. In some cases, the disease develops in one eye but does not affect the other for many ears.

Symptoms vary and may include:

Recent advances in eye research offer new hope to victims of AMD. Those who have the "wet" type of AMD are frequently responding to injection of medication into the eye which is improving the vision in many. There has been significant visual recovery in some patients not seen before with other types of treatments. These injections often do require repeated treatment. The treatment is usually a painless outpatient procedure. These medications inhibit the growth of abnormal blood vessels in the eye.

At present, no proven treatment exists for the dry form of AMD. However, researchers have discovered that a healthy macula has two yellowish pigments--the antioxidants known as lutein and zeaxanthin--that may block harmful blue light from damaging the retina. Studies suggest that nutritional supplements containing these antioxidants as well as zinc slow degeneration. A caution exists for those who smoke: there is a link between smoking, zinc consumption and lung cancer and therefore it is recommended to take a formulation that does not include zinc as part of the supplement.

No one knows how to prevent AMD but the following practices may help to delay the onset of the disease:

Until scientists find a cure or lasting treatment for AMD, patients still have the reality of the presence of this disease in their lives. They should consult an ophthalmologist and a low vision specialist for advice about products and rehabilitation techniques to maximize remaining vision. One can also receive individual training to maintain mobility and independence in daily living.

It is also important for a patient to:

The are many promising avenues of scientific investigation into AMD to find a lasting cure or are preventive for AMD. Areas of investigation include:

We hope in the future to prevent this disease which can be so debilitatating. We do have better treatments now for AMD than existed even in 2004.