Houston Methodist. Leading Medicine.
Houston Methodist. Leading Medicine

Macular Degeneration

Conditions & Treatments

Macular Degeneration

Age-related Macular Degeneration (AMD, or ARMD) is the number one cause of legal blindness in people over the age of 60 in the United States. The term ‘macula’ refers to the central part of the retina. The retina is the back, inner lining of the eye which, like the film in a camera, captures light and sends signals to the optic nerve. The macula, being in the center of the retina, allows us to see in detail, i.e. for reading, driving, watching TV, and recognizing faces. In AMD, the macula is damaged, resulting in poor central vision. Since the peripheral retina is not involved, AMD cannot lead to total blindness.

Normal visionNormal vision

Graphical representation of a scene as viewed by an individual with AMDGraphical representation of a scene as viewed by an individual with AMD

There are two main types of AMD—dry and wet. The dry, or atrophic, type is the most common, occurring in 80-90% of AMD patients. In the dry type, degenerative changes are seen in the macula, most commonly referred to as drusen (small, yellow deposits under the retina) and Retinal Pigment Epithelium (RPE) changes. Dry AMD results in mild to moderate vision loss. The wet, or neovascular, type occurs in 10-20% of AMD patients, and can result in more significant vision loss. It results from new blood vessel growth under the retina, which can leak and cause fluid and/or blood to build up in the macula. It is this wet type, however, that can be treated with injections, lasers or surgery, often with preservation of good vision.

The most common risk factor for AMD is advancing age. In general, AMD tends to be more common in females and Caucasians with light eye color. Genes also play an important role in determining the risk level for AMD, as well as smoking and drug use.

If you are diagnosed with dry macular degeneration, preventative measures can be taken to slow down its progression, including avoiding ultraviolet light by wearing protective sunglasses when outdoors, taking certain nutritional supplements, and monitoring subtle vision changes using a square grid called an Amsler grid. For more information on AMD, please click on the image to the right to download an informational brochure. If you have any concerns, please see one of our eye doctors for a general eye exam, which will include a detailed look at the retina.