AGE-RELATED MACULAR DEGENERATION

WHAT IS AGE-RELATED MACULAR DEGENERATION? (AMD)
AMD affects the macula, which is the part of the retina responsible for central vision. Light passes through the eye and focuses on the macula, where it is translated into an electrical impulse and sent to the brain. The result is the ability to see details like words on a printed page and physical features. As we age, the macula can weaken and its cells begin to atrophy. Central vision can be heavily affected, while peripheral vision frequently remains the same. Daily activities such as reading and driving can become difficult, if not altogether impossible.

Most cases of AMD are related to aging. It also can occur as a side effect of some drugs, and it appears to run in families. AMD is leading cause of blindness in people over 65.

WHAT IS THE DIFFERENCE BETWEEN DRY AND WET MACULAR DEGENERATION?

DRY (ATROPHIC) MACULAR DEGENERATION- is the most prevalent form of the disease. It affects about 90% of those with AMD. A common feature of the dry form is the existence of drusen. Drusen are yellow deposits found in the retina. As drusen increase in size or number, the risk of vision loss increases.

WET (EXUDATIVE) MACULAR DEGENERATION - accounts for about 10% of all diagnosed cases. This is caused by abnormal blood vessels that grow through the retina and leak resulting in a build up of blood or fluid within the macula. This usually leads to more serious vision loss in a short period of time.

WHAT ARE THE SYMPTOMS OF MACULAR DEGENERATION?
Macular degeneration will cause a range of symptoms in different people. The most common symptoms are words appearing blurry on a printed page, a dark or empty area appearing in the center of vision, or straight lines looking curved or distorted. The vision changes can occur slowly or suddenly.

HOW IS MACULAR DEGNERATION DIAGNOSED?
Often, your eye doctor will detect early signs of AMD before you experience symptoms. This usually is accomplished through an examination of the macula with a specialized instrument that gives the doctor a magnified view of the tissue. If the wet form is suspected, the doctor may due a test called flourescein angiography where a specialized dye is injected into a vein and series of photographs are taken of the macula.

WHAT CAUSES MACULAR DEGENERATION?
The exact causes of age-related macular degeneration are still unknown. The dry form of AMD may result from the aging and thinning of macular tissues, depositing of pigment in the macula, or a combination of the two processes. With wet AMD, new blood vessels grow beneath the retina and leak blood and fluid. This leakage causes retinal cells to die and creates blind spots in the central vision.

WHAT ARE THE RISK FACTORS OF MACULAR DEGENERATION?

AGE: The most common factor is age. As we get older, the risk of getting AMD greatly increases. At age 50 the risk is estimated to be 2%. The risk increases to 30% at 75.

HEREDITY: Those with immediate family members diagnosed with AMD can be at a greater risk.

GENDER: Women may be at a greater risk of developing AMD than men. This might be attributed to lower estrogen levels in postmenopausal women.

DIET: Inadequate intake of antioxidants, consumption of alcohol, saturated fats and cholesterol can create free radical reactions that can harm the macula.

HEART DISEASE: Poor blood circulation due to high blood pressure or other vascular disease can lower the blood flow to the eyes and lead to macular degeneration.

SMOKING: Smoking increases the risk of getting AMD.

SUN: Significant cumulative light exposure may increase the risk of getting AMD.

LIFESTYLE: Limited physical activity and obesity are also associated with AMD.

IS THERE A TREATMENT FOR MACULAR DEGENERATION?
There is no cure for macular degeneration, but treatment may be able to delay its progression or even improve your vision.

VITAMINS AND MINERALS: Dry macular degeneration can be treated under certain circumstances with a high-potency vitamin and antioxidant supplement. Recently, a national study called the age-related eye disease study (AREDS) was completed that showed that a combination of certain vitamins and antioxidants can reduce the progression of dry macular degeneration in individuals who are at a high risk for vision loss from the disease. The AREDS formula is the first proven treatment for dry macula degeneration.

LASER TREATMENT: Laser photocoagulation can help wet AMD patients by destroying or sealing new blood vessels to prevent leakage. Unfortunately, this procedure can produce scars, which are perceived as blind spots in the vision. It is rarely used since the inception of photodynamic therapy.

PHOTODYNAMIC LASER THERAPY: Photodynamic therapy is a refinement of standard laser treatment for wet macular degeneration. A light-sensitive dye called verteporfin is injected and collects in the abnormal blood vessels in the retina. The laser combines with that dye to produce a very localized reaction that closes off the abnormal blood vessels, eliminating leakage and hemorrhage and sparing the vision cells above the vessel.

TRANSPUPILLARY THERMOTHERAPY: Another form of photocoagulation currently in use is transpupillary thermotherapy. This technique uses a laser to gently heat the back of the eye to produce a localized area of hyperthermia to close off leaky blood vessels. It sometimes is used in cases where PDT is contraindicated.

OTHER TREATMENTS: There are several promising new treatments currently in the research phase. The goal is to someday find a cure for this blinding disease.