What is Macular Degeneration:
Macular degeneration (AMD) is a disease of the macula--a small area in the center of the retina. The macula is responsible for fine detail vision needed for reading, driving, and many other visual tasks. When the macula is not working properly, a patient may experience blurry, distorted, or dark central vision. Macular Degeneration is the most common cause of vision loss in patients over the age of 50.
What causes Macular Degeneration?
Many older patients develop AMD as part of the normal aging process. Major risk factors include:
-Genetic predisposition or family history of AMD
-Age older than 50
Many people with AMD have deposits under the retina called drusen. As they grow in number and size, there is an increased risk for advanced AMD.
The two most common forms of AMD are dry and wet.
Dry Macular Degeneration
Ninety percent of people with AMD have the “dry” form. This condition is caused by damage and results in thinning of the macular tissue. Vision loss is usually gradual. Many people with this form of AMD may have difficulty adjusting to changes in light. For example, they may find it takes them some time to adjust to seeing indoors when they come in from outside.
Dry AMD Dry AMD OCT
Wet Macular Degeneration
Ten percent of people with AMD have the “wet” form. Many of these people develop significant vision loss. Wet AMD results when abnormal blood vessels form underneath the retina. This new vessels bleed and leak fluid resulting in blurring of the central vision. The vision loss may be rapid and severe.
Wet AMD Wet AMD FA Wet AMD OCT
Macular Degeneration Symptoms
AMD can cause different symptoms for different people. Many may be asymptomatic in the early stages. Some times only one eye loses vision, while the other eye continues to see well for many years.
-words on a page may be blurry
-a dark or empty area may appear in the center of the vision
-straight lines may become distorted as seen below:
How is AMD Diagnosed?
Your ophthalmologist can detect AMD during a medical eye exam including:
Vision and amsler grid testing
dilated eye examination
specialized tests including Fluorescein angiography (uses special dye and photographs to illuminate abnormal blood vessels) and Optical Coherence Tomography (OCT).
How is AMD Treated?
Antioxidant vitamins and zinc may reduce the impact in some people. The latest large scientific study on AMD and nutritional supplements fourth that people at risk for developing advanced stages of AMD lowered their risk by at least 25 percent when treated with a high-dose combination of the following:
Vitamin C 500 mg
Vitamin E 400 iu
Lutein 10 mg
Zeaxanthin 2 mg
Zinc 80 mg
Copper 2 mg
Among those who have either no AMD or very early AMD, the supplements do not appear to be beneficial. Family members of patients with AMD should check with their doctor before taking these vitamins themselves. Talk to your ophthalmologist to find out if you are at risk for developing advanced AMD, and to learn if supplements are recommended for you. It is important to remember that vitamin supplements are not a cure for AMD nor will they give you back vision that you may have lost.
Anti-VEGF Treatments, Laser, and PDT
The common treatment for wet AMD involves injecting a drug into the eye that stops blood vessel growth and bleeding. The drugs, known as VEGF-blockers, target a specific chemical in the eye that causes abnormal blood vessels to grow under the retina. That chemical is called vaso-endothelial growth factor (VEGF). These treatments help to stop the progression of further vision loss, and in some, may help to improve vision.
Laser treatment may still be used in some cases of wet AMD to slow or stop leaking blood vessels. PDT uses a combination of a special medication and “cold” laser treatment to treat the abnormal vessels.
These procedures may save more of our sight overall, but they are not cures that restore normal vision. Even with advanced medical treatment, many people with AMD still experience vision loss.
Click on the following link to the American Academy of Ophthalmology EyeSmart page for more information.
(*the above information was adapted from the handout “Macular Degeneration, A closer Look”, provided by the American Academy of Ophthalmology.)