Age-related Macular Degeneration is a common eye condition and a leading cause of vision loss among people age 50 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 people, 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 no 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.
About the Macula
The macula is made up of millions of light-sensing cells that provide sharp, central vision. It is the most sensitive part of the retina, which is located at the back of the eye. The retina turns light into electrical signals and then sends these electrical signals through the optic nerve to the brain, where they are translated into the images we see. When the macula is damaged, the center of your field of view may appear blurry, distorted, or dark.
Who is at Risk
Age is a major risk factor for AMD. The disease is most likely to occur after age 60, but it can occur earlier. Other risk factors for AMD include:
Smoking. Research shows that smoking doubles the risk of AMD.
Race. AMD is more common among Caucasians than among African-Americans or Hispanics/Latinos.
Family History and Genetics. People with a family history of AMD are at higher risk. At last count, researchers had identified nearly 20 genes that can affect the risk of developing AMD. Many more genetic risk factors are suspected. You may see offers for genetic testing for AMD. Because AMD is influenced by so many genes plus environmental factors such as smoking and nutrition, there are currently no genetic tests that can diagnose AMD, or predict with certainty who will develop it. The American Academy of Ophthalmology (link is external) currently recommends against routine genetic testing for AMD, and insurance generally does not cover such testing.
How Lifestyle Makes a Difference
Researchers have found links between AMD and some lifestyle choices, such as smoking. You might be able to reduce your risk of AMD or slow its progression by making these healthy choices:
- Avoid smoking
- Exercise regularly
- Maintain normal blood pressure and cholesterol levels
- Eat a healthy diet rich in green, leafy vegetables and fish
How AMD is Detected
The early and intermediate stages of AMD usually start without symptoms. Only a comprehensive dilated eye exam can detect AMD. The eye exam may include the following:
Visual Acuity Test
This eye chart measures how well you see at distances.
Dilated Eye Exam
Your eye care professional places drops in your eyes to widen or dilate the pupils. This provides a better view of the back of your eye.
Amsler Grid
Your eye care professional also may ask you to look at an Amsler grid. Changes in your central vision may cause the lines in the grid to disappear or appear wavy, a sign of AMD.
Fluorescein Angiogram
In this test, which is performed by an ophthalmologist, a fluorescent dye is injected into your arm. Pictures are taken as the dye passes through the blood vessels in your eye.
Optical Coherence Tomography
OCT uses light waves and can achieve very high-resolution images of any tissues that can be penetrated by light.
During the exam, your eye care professional will look for drusen, which are yellow deposits beneath the retina. Most people develop some very small drusen as a normal part of aging. The presence of medium-to-large drusen may indicate that you have AMD.
How to Treat AMD
Early AMD
Currently, no treatment exists for early AMD, which in many people shows no symptoms or loss of vision. Your eye care professional may recommend that you get a comprehensive dilated eye exam at least once a year. The exam will help determine if your condition is advancing.
As for prevention, AMD occurs less often in people who exercise, avoid smoking, and eat nutritious foods including green leafy vegetables and fish. If you already have AMD, adopting some of these habits may help you keep your vision longer.
Intermediate and Late AMD
Researchers at the National Eye Institute tested whether taking nutritional supplements could protect against AMD in the Age-Related Eye Disease Studies (AREDS and AREDS2). They found that daily intake of certain high-dose vitamins and minerals can slow the progression of the disease in people who have intermediate AMD, and those who have late AMD in one eye.
Advanced Neovascular AMD
Neovascular AMD typically results in severe vision loss. However, eye care professionals can try different therapies to stop further vision loss – including injections, photodynamic therapy and laser surgery.
Dr. Bantz is a general eyecare optometrist with a focus on ocular disease and contact lenses at VisionQuest Eyecare. A recent graduate of Indiana University’s School of Optometry, Dr. Bantz received his undergraduate degree from Butler University. He specializes in eyecare for patients of all ages, as well as contact lenses.