Macular degeneration is a condition of the eye that results in impairment of sharp, central vision. The condition is also called age-related macular degeneration (AMD) because it primarily affects adults age 65 and older. Macular degeneration is the leading cause of vision loss in older adults.

What Causes Macular Degeneration

The macula is the most sensitive part of the retina, which is the light-sensitive tissue located at the back of the eye that converts light to electrical impulses and sends these impulses to the brain via the optic nerve. The macula assists the retina in processing fine details. When damaged, clear central vision and the ability to perceive fine details are lost.

Types of Macular Degeneration

The two most common types are dry and wet macular degeneration. The dry form of the disease is the most common. About 85-90% of all cases are of this type. Dry macular degeneration results from the slow breakdown of cells in the macula, resulting in a gradual loss of central vision. The wet form comprises only about 10-15% of all cases, but is a more serious and rapidly progressing form of the condition. Wet macular degeneration is caused by retinal abnormalities that decrease oxygen flow to the area and results in fissures, or cracks, in the retina. The body responds by creating new blood vessels to bring oxygen to the retina. These vessels are fragile and often leak or bleed into the retinal tears, giving the condition its name. In addition to leaking fluids into the retina, these blood vessels also displace the macula by putting pressure on it, much as tree roots can displace a sidewalk.

Age-related Macular Degeneration Statistics for the U.S. and Canada

While wet AMD accounts for relatively fewer cases, it causes the vast majority of vision loss. According to a 2004 study published in the Archives of Ophthalmology, 1.75 million Americans are affected with the condition, and it is expected that the number will increase to 3 million by 2020 as the U.S. population continues to age. Overall, about 2% of Americans under age 60 develop the condition, and the risk jumps to a 30% overall chance of developing the condition in Americans age 75 and older. In Canada, the prevalence is even higher, with a staggering 23% of Canadians ages 43 to 64 developing the condition. True to its name, the incidence of age-related macular degeneration rises to 56% for Canadians ages 65 to 84.

Symptoms of macular degeneration

Early symptoms of the dry form include blurred vision that may improve in bright light, and a small blind spot in central vision that gradually increases over time. One common early symptom of wet type is the perception of straight lines as being crooked, due to the displacement of the macula. Those with wet macular degeneration may also experience a blind spot in central vision.

Risk Factors for Macular Degeneration

The cause isn't fully understood, but doctors and researchers have identified key risk factors. Some of these risk factors are hereditary and cannot be modified. These include family history of the disease, age, race, eye pigmentation, and gender. Light skinned people and those with blue eyes are more likely to develop the condition, as are women when compared with men.

Modifiable risk factors include smoking, poor diet, high blood pressure, obesity and excessive exposure to sunlight.

Decrease Risk with Good Lifestyle Choices

Making lifestyle choices that protect your vision can drastically reduce the risk of developing macular degeneration, and improve overall health as well.

Making good choices is especially important for those with non-modifiable risk factors. Through smoking cessation, a nutrient dense diet, controlling blood pressure, maintaining ideal body weight, and using appropriate sunlight protection, a person with some non-modifiable risk factors can reduce the risk of losing their vision to this degenerative eye disease.

Author's Bio: 

Beverly OMalley explores the causes of many smoking related diseases at where you can read more smoking facts that reveal that age related macular degeneration could be among the many harmful cigarette smoking effects on the body.