What is Macular Degeneration?

Macular Degeneration is the leading cause of blindness in older adults. http://www.macular.org/disease.html. This is the most common of a number of physical disturbances to the center of the retina called the macula. The macula, smaller than the size of the capital letter "o" in this sentence, is the part of the retina, which is capable of our most acute and detailed vision. Age Related Macular Degeneration (AMD) is the most common form, with problems typically not presenting until the patient is 60 or older.

The macula is responsible for our central vision with the densest concentration of the photoreceptor cells that allow vision, and it is the area that is responsible for our sharp central vision. Because of the central location of the macula and the way light enters the eye, macular degeneration leads to the loss of central vision. This area of the retina is critical for seeing detail, and most of the color receptors are also found here. Decreased vision and even blindness are the outcome of AMD. Legal blindness means that a person can see 20/200 or less with eyeglasses. Even with a loss of central vision, some color vision and peripheral vision may remain clear. Vision loss usually occurs gradually and typically affects both eyes at different rates.

As AMD advances, vision becomes so compromised that ordinary everyday activities become difficult. Watching TV, reading, driving, seeing a picture on a wall, or reading a road sign can be extremely difficult. Studies reported in 2002 that there were 5 to 10 million cases of AMD in the United States alone. And these numbers are increasing every year as the average age of our population rises. There are some studies that suggest that almost one quarter (25%) of adults over the age of 65 show some evidence of deterioration in the macular region. For those over 74, some studies report the incidence as 37%. http://www.mdsupport.org/library/numbers.html.

What Causes Macular Degeneration?

Research scientists are learning more and more about the possible causes of Macular Degeneration, both the Juvenile forms and Age-related Macular Degeneration. There are several research studies that indicate hereditary links with the various forms of Juvenile Macular Degeneration. Some of these have similar genetic properties they share with AMD. One gene that has been identified is the ATP-binding cassette transporter gene (ABCR). This gene is implicated in AMD, Stargardt’s disease, fundus flavimaculatus, recessive retinitis pigmentosa, cone dystrophy, and cone-rod dystrophy.

Each cell of our body, including the specialized cells in the retina of the eye, needs enough energy to carry out its functions. Some of these include: normal cellular duplication, removal of cellular waste products, maintaining normal circulation, maintenance of cellular integrity, and proper intra- and extra-cellular communication. As Macular Degeneration progresses, deterioration occurs to the retina and surrounding tissue, and vision is impaired as a result. In some cases the "dry" form becomes "wet" as a result of leakage or bleeding from weakened blood vessels.

How is Macular Degeneration Detected?

Declining vision noticed by the patient, or by a doctor during a routine eye exam may be the first indicator of macular degeneration. Often a patient notices that their glasses no longer help as much with reading or general vision.

The formation of new blood vessels and exudates, or "drusen," from blood vessels in and under the macular is often the first physical sign that macular degeneration may develop.

In addition, the following signs may be indicative of macular problems. Anyone experiencing these symptoms should consult an ophthalmologist immediately.

• Straight lines appear distorted or “wavy” and, in some cases, the center of vision appears more distorted than the rest of the scene.
• A dark, blurry area or "white-out" appears in the center of vision.
• Color perception changes or diminishes.

The following are NOT known to be linked to macular degeneration: floaters (moving spots caused by debris floating in the vitreous fluid between the lens and the retina); dry eye syndromes; cataracts and cataract surgery.