Macular degeneration Health Article

Definition

Macular degeneration is an eye disorder that makes it difficult to see fine details. The condition affects the macula, the part of the retina responsible for central vision.

Alternative Names

Age-related macular degeneration (AMD), AMD, Senile macular degeneration (SMD)

Causes, incidence, and risk factors

Damage to the macula can gradually destroy central vision, which is used to read and see objects clearly.

Two types of macular degeneration (AMD) exist:

• Dry macular degeneration occurs when the macula becomes thin and dries out. Small yellow deposits, called drusen, form under the macula. As these drusen increase in size and number, they create a blurred spot in the central vision of the eye. Almost all people with macular degeneration have the dry form.
• Wet macular degeneration occurs when abnormal blood vessels grow under the macula and retina (this is called choroidal neovascularization). These vessels can leak blood and fluid, damaging the macula. Vision loss in the central vision can occur very quickly. Only about 10 percent of people with macular degeneration have this form, but it causes most of the vision loss associated with the condition.

Scientists aren’t sure what causes AMD. The disease is most common in people over 60, which is why it is often referred to as age-related macular degeneration.

Other risk factors are:

• Caucasian race
• Cigarette smoking
• Family history
• Female gender
• Obesity

Symptoms

At first you may not have symptoms. As the disease progresses, your central vision can be affected.

The most common symptom in dry AMD is blurred vision. As the disease progresses, you may need more light to read or perform everyday tasks. The blurred spot in the center of vision gradually gets larger and darker. In the later stages, you may not be able to recognize faces until people are close to you.

AMD typically does not affect side (peripheral) vision. This is very important, because it means you will never have complete vision loss from this disease.

The most common early symptom of wet macular degeneration is that straight lines appear distorted and wavy. You may also notice a small dark spot in the center of your vision that gradually gets larger.