Age-Related Macular Degeneration

Age-Related Macular Degeneration (AMD) is a disease that gradually destroys sharp, central vision. Central vision is critical in common daily tasks such as reading and driving. It is also crucial when trying to see objects clearly. Age-Related Macular Degeneration (AMD) is the leading cause of blindness in people over the age of 50, affecting millions of people worldwide. In addition, the prevalence of AMD is expected to nearly double by 2020. Though often experienced as a sudden distortion or loss of vision, AMD is actually a slow progressive deterioration of the macula (the part of the eye needed to provide sharp central vision). The individual is often unaware of the condition until serious, many times irreversible visual symptoms occur.

What happens to the eye with Macular Degeneration? The pathology is somewhat similar to that of the normal aging process of the retina. Normal respiration in the body produces oxidants, free radicals and reactive oxygen species (ROS). These lead to disease. Some protection from the effects caused by free radicals may be offered through antioxidants. Keeping a balance between antioxidants and free radicals is crucial in preventing damage from tissue injury and inflammation. The body’s immune response to chronic inflammation can lead to the damage and possible death of the macular retina pigment epithelium.

Dry AMD occurs when the light-sensitive cells in the macula slowly break down. This causes a gradual blurring in the central vision of the affected eye. As dry AMD progresses, a blurred spot occurs in the center of the individual’s vision. Eventually, as less of the macula functions, central vision is lost in the affected eye.

Wet AMD occurs when abnormal blood vessels behind the retina begin to grow under the macula. These blood vessels are very fragile. They often leak blood and fluid. The blood and fluid raise the macula from its normal location at the back of the eye. Damage to the macula occurs rapidly. Thus, central vision can be lost very rapidly.

A message from the Nature's Eye Rabbit

Age-Related Eye Disease Studies

AREDS

The Age-Related Eye Disease Study (AREDS) was a major landmark study sponsored by the National Eye Institute. This study followed over 3,500 individuals in various stages of AMD. Participants took high levels of antioxidant vitamins and zinc over a period of ten years. The study concluded that patients with moderate to advanced AMD decreased their risk of AMD-associated vision loss by 19% by taking a high-potency antioxidant and a mineral supplement every day.

AREDS II

The Age-Related Eye Disease Study II (AREDS II) was a multicenter randomized clinical trial that was designed to determine the effect of high oral doses of lutein, zeaxanthin, and omega-3 fatty acids in patients with moderate to advanced AMD. The study concluded that the addition of zeaxanthin and lutein to the original AREDS formulation slowed down the AMD progression to advanced disease.

The Risk Factors

Many risk factors predispose an individual to AMD. Some risk factors are modifiable, that is, an individual can do something about them. These include smoking, hypertension, hypercholesterolemia, obesity, exposure to sunlight, and poor nutrition. Some risk factors are not modifiable, that is, an individual cannot change them. Some nonmodifiable risk factors include sex, age, heredity, race, and certain physical traits.