AMD/Low Vision Awareness - February 16, 2010 Newsletter

February is AMD/Low Vision Awareness Month

EHE Newsletter, Volume 10, Number 7
February 16, 2010

Age–related Macular Degeneration (AMD) is a chronic eye disease associated with aging that gradually destroys the macula. The macula is the part of the eye that provides sharp, central vision needed for seeing objects clearly and for performing common daily tasks such as reading, driving and recognizing faces. If left untreated, AMD can result in severe vision loss and blindness.

According to research by Prevent Blindness America and the National Eye Institute (NEI), AMD currently affects the vision of more than two million Americans aged 50 and older. It is also the leading cause of permanent impairment of reading vision and fine, close–up vision among people aged 65 years and older. In light of the rapidly aging U.S. population, the Centers for Disease Control and Prevention (CDC) estimates that the number of people with AMD will reach 2.95 million by 2020. Despite the damaging effects of this disease, AMD is still a relatively unknown condition. The promising news is that the effects of AMD can be diminished through early detection and treatment by an eye care professional. The U.S. Department of Health and Human Services has declared February to be AMD/Low Vision Awareness Month in order to educate Americans about the disease.

Types of Age-related Macular Degeneration

Age–related macular degeneration is classified as either "dry" (non–neovascular) or "wet" (neovascular). Dry AMD is the most common form of this disease, accounting for 85 to 90 percent of AMD diagnoses. Wet AMD affects about ten percent of all people with AMD and is more severe than the early and intermediate stages of dry AMD.

Dry AMD: Dry AMD is characterized by the presence of yellow deposits, called "drusen," in and around the macula. In general, drusen does not cause changes in vision. As drusen grow in size and increase in number, however, they may lead to a dimming or distortion of vision that is most noticeable during reading. According to the NEI, Dry AMD has three stages that can occur in one or both eyes. These stages are:

• Early: Individuals with early dry AMD have either small drusen or a few medium–sized drusen. At this stage, there may not be any symptoms or vision loss.
• Intermediate: Individuals with this stage of dry AMD have many medium–sized drusen or one or more large drusen. Intermediate AMD often has no symptoms, though some individuals may see a blurred spot in the center of their vision. These individuals often need additional light to read.
• Advanced: In addition to drusen, people with advanced dry AMD have a breakdown of light–sensitive cells and supporting tissue in the central retinal area. This breakdown can cause a blurred spot in the center of vision. Over time, this blurred spot may grow larger and darker, blocking more and more central vision. Individuals with advanced dry AMD may have difficulty reading or recognizing faces until they are very close.

Wet AMD: Wet AMD occurs when abnormal blood vessels behind the retina begin to grow underneath the macula. This process is called "choroidal neovascularization." These new blood vessels can be fragile and may leak blood and fluid into the eye which raise the macula from its normal place at the back of the eye, resulting in rapid damage. A common symptom of Wet AMD is that straight lines appear wavy. Damage caused by wet AMD may also lead to scarring of the retina. Early diagnosis of Wet AMD is critical in order to preserve eyesight and expand treatment options.

As the dry form of AMD can change into the wet form, it is very important for individuals to monitor their eyesight carefully and to see their ophthalmologist on a regular basis. Although only approximately ten percent of individuals with AMD develop the wet form of the disease, that ten percent accounts for the majority of people who experience serious vision loss.

Individuals who experience any of the symptoms of Wet or Dry AMD should contact their eye doctors immediately for a comprehensive examination. Central vision loss that is caused by AMD cannot be restored. Low vision devices, however, such as telescopic and microscopic lenses can be prescribed to maximize existing vision.

Risk Factors

The exact cause of AMD is not known. According to the NEI, risk factors for AMD include:

• Age: Age is the greatest risk factor. Studies show that individuals over age 60 are at greater risk than other age groups
• Smoking: Smoking may increase the risk of AMD
• Obesity: Research studies suggest a link between obesity and the progression of early and intermediate AMD to advanced AMD
• Race: Caucasians are much more likely to lose vision from AMD than African–Americans
• Family history: Those with immediate family members who have AMD are at higher risk of developing the disease
• Gender: Women appear to be at greater risk than men

AMD is a leading cause of vision loss for Americans age 65 and older. Such individuals should visit their eye doctors regularly, watch for signs of AMD and lead a healthy lifestyle.

Prevention

Regular eye exams are vital in preventing vision loss. Regular visits to an ophthalmologist can help detect AMD and other eye diseases in their early stages when treatment is most effective. According to the NEI, an eye care professional may suspect AMD if an individual is over age 60 and has had recent changes to his or her central vision. AMD is detected during a comprehensive eye exam that includes:

• Visual acuity test: This eye chart test measures how well an individual sees at various distances.
• Dilated eye exam: Drops are placed in the eyes to widen, or dilate, the pupils. The eye care professional then uses a special magnifying lens to examine the retina and optic nerve for signs of AMD and other eye problems. After the exam, the patient’s close–up vision may remain blurred for several hours.
• Tonometry: An instrument measures the pressure inside the eye. Numbing drops may be applied to the eye for this test.

During an eye exam, the patient may also be asked to look at an Amsler grid. This grid can help detect visual distortions that might occur as early signs of AMD. The pattern of the grid resembles a checkerboard with a fixation dot in the center. While staring at the dot, an individual may notice that the straight lines in the pattern appear wavy or that some of the lines are missing — possible signs of AMD.

Over the past two decades, there has been significant research done on eye health which links diet and nutrition with a decreased risk of AMD. According to this research, adding certain nutrients to one’s diet every day — either through foods or supplements — can help preserve vision and prevent age–related eye diseases. Research has identified five essential nutrients which promote healthy vision and may reduce the risk of eye diseases such as AMD:

• Lutein and zeaxanthin: Lutein and zeaxanthin are important nutrients that are naturally found together in colorful fruits and vegetables such as spinach, kale, corn, oranges and tangerines. Lutein and zeaxanthin are deposited in various tissues of the eye, including the macula, retina, and lens, and act as antioxidants in helping to protect and maintain healthy cells.
• Essential fatty acids: Fatty acids such as DHA and EPA have been shown to be important factors in visual development and retinal function. Low levels of these fatty acids have been associated with AMD. DHA and EPA are found in whole–grain foods, chicken, eggs and fleshy fish such as tuna, salmon and herring.
• Vitamin C: Vitamin C supports the health of ocular blood vessels. Virtually all cells of the body depend on vitamin C, including cells of the eye where it is actively concentrated in all tissues. Vitamin C is found in fruits and vegetables such as oranges, grapefruit, strawberries, papaya, green peppers and tomatoes.
• Vitamin E: Vitamin E is an antioxidant that is found in nuts, fortified cereals, almonds, pecans, sweet potatoes, sunflower seeds and vegetable oils such as safflower oil and corn oil. It promotes the health of cell membranes and DNA repair, and plays a significant role in immune system function.
• Zinc: Zinc is an essential trace mineral that is found in extra–lean red meat, poultry, liver, oysters, lobster, milk, baked beans and whole grains. It is vital to the process of bringing vitamin A from the liver to the retina in order to produce melanin, a protective pigment in the eyes. Zinc is recommended for individuals who are at higher risk of developing AMD.

Additionally, evidence suggests that when zinc and vitamins C and E are taken in combination with other essential nutrients, the progression of AMD can be slowed by 25 percent and visual acuity loss can be slowed by 19 percent. In addition to a healthy diet, leading a healthy lifestyle can also play a role in reducing the risk of developing AMD. Most importantly:

• Do not smoke
• Maintain normal blood pressure
• Control your weight
• Exercise

Use AMD/Low Vision Awareness Month as a time to educate yourself and your loved ones about one of the leading causes of blindness in the world. Preventing and/or managing eye disease is an essential component of a healthy, happy and productive life.

MEDICAL DISCLAIMER: The information is not intended to constitute medical advice and is not a substitute for consultation with a physician or other health care provider. Individuals with specific complaints should seek immediate consultation from their personal physicians.