Macular Degeneration

Age Related Macular Degeneration (AMD) is a common eye condition and a leading cause of vision loss among individuals age 60 and older. It causes damage to the macula, a small spot near the center of the retina, and the part of the eye needed for sharp, central vision which lets us see objects that are straight ahead.

In some individuals, AMD advances so slowly that vision loss does not occur for a long time. In others, the disease progresses faster and may lead to a loss of vision in one or both eyes. As AMD progresses, a blurred area near the center of vision is a common symptom. Over time, the blurred area may grow larger or you may develop blank spots in your central vision. Objects also may not appear to be as bright as they used to be.

AMD by itself does not lead to complete blindness with zero ability to see. However, the loss of central vision in AMD can interfere with simple everyday activities, such as the ability to see faces, drive, read, write, or do close work, such as cooking or fixing things around the house. 

Risk factors include being over the age of 60, smoking, being Caucasian, and having a family history of AMD. Researchers have found links between AMD and some lifestyle choices, such as smoking (increases risk twofold). You might reduce your risk of AMD or slow its progression by making healthy life choices (avoid smoking, exercise regularly, maintain normal blood pressure and cholesterol levels, eat a healthy diet rich in green leafy vegetables and fish, etc).

There are three stages of AMD defined in part by the size and number of drusen under the retina. Drusen are yellow deposits under the retina that are made up of proteins and lipids. They are thought to be byproducts of the highly metabolic rods and cones in the retina. They may also contain inflammatory components of the immune system. It is possible to have AMD in one eye only, or to have one eye with a later stage of AMD than the other.

Early AMD: Early AMD is diagnosed by the presence of medium-sized drusen, which are about the width of an average human hair. People with early AMD typically do not have vision loss.

Intermediate AMD: People with intermediate AMD typically have large drusen, pigment changes in the retina, or both. These changes can only be detected during an eye examination. This level of AMD may cause some vision loss but most people will not experience any symptoms.

Late AMD: In addition to drusen, people with late AMD have vision loss from damage to the macula. There are two types of late AMD: Geographic Atrophy and Neovascular AMD.

Geographic Atrophy: In geographic atrophy, there is a gradual breakdown of the light-sensitive cells in the macula that convey visual information to the brain, and of the supporting tissue beneath the macula. These changes can cause vision loss.

Neovascular AMD: Neovascular means "new vessels.” In neovascular AMD (also called “Wet AMD”), abnormal blood vessels grow underneath the retina. These vessels can leak fluid and blood, which may lead to swelling and damage of the macula. The damage may be rapid and severe, unlike the more gradual course of geographic atrophy.

It is possible to have both geographic atrophy and neovascular AMD in the same eye, and either condition can appear first.