Macular degeneration is a chronic condition that causes central vision loss. It is the leading cause of blindness in people over 60 and affects many millions of people worldwide. The condition is rarely diagnosed before age 65 and is most often seen in adults 75 or older. It is often called age-related macular degeneration, or AMD.
The exact cause of AMD is not known. But there are a number of risk factors that may play a role. The same things that put people at risk for heart disease and stroke also put them at risk for AMD.
These risk factors include:
- High blood pressure
- High cholesterol
- Low levels of nutrients and minerals such as zinc and vitamins
Risks that cannot be controlled include:
- Age – people over the age of 60 are at greater risk
- Family history – if AMD runs in your family, or if you have a certain abnormal gene, you may have a higher risk
- Gender – women are more likely than men to get AMD
- Race – AMD is more common in white people’
Early detection is key to avoiding vision loss. AMD symptoms include blurriness, wavy lines or a blind spot, all of which make it difficult to read and/or see fine details. Straight lines or faces may appear wavy, doorways may seem crooked and objects may appear smaller or further away than they really are.
AMD occurs when the macula—the central portion of the retina that is important for reading and color vision—becomes damaged. AMD is a single disease, but it can take 2 different forms: dry and wet.
Dry AMD occurs when the blood vessels under the macula become thin and brittle. Small yellow deposits (drusen) form and can interfere with vision. Almost all people with macular degeneration start with the dry form.
Wet AMD occurs in only about 10% of people diagnosed with macular degeneration. New abnormal and very fragile blood vessels that leak blood and fluid grow under the macula (a process called choroidal neovascularization) This form causes most of the vision loss associated with the condition.
Wet AMD is the more serious form, with more than 200,000 people in the U.S. diagnosed every year. Without treatment, patients can lose their central vision over time, leaving only peripheral (side) vision. The symptoms can occur suddenly or gradually over time. Early detection and treatment can help avoid severe vision loss.