What is Age-Related Macular Degeneration?
Age-related macular degeneration (AMD) is an eye disease that causes damage to the macula, the small central portion of the retina, which is used for sharp, central vision. According to the National Eye Institute, AMD is the leading cause of vision loss among people age 50 and older. Noticeable vision loss may not occur for a long time because of the slow-moving nature of the disease. Those with AMD may develop blank spots in their central vision and objects may not appear as bright in color. It is also possible to only develop AMD in one eye and not the other. While the disease may not lead to complete blindness, it may interfere with simple, everyday tasks.
AMD Stages
AMD can progress in severity through three stages. Since there are only a few, unnoticeable symptoms in the early stages, it is crucial to have regular comprehensive eye exams to detect AMD symptoms.
Early AMD: medium-sized, yellow deposits composed of fat and protein, called drusen, are found under the retina – typically no vision loss experienced.
Intermediate AMD: large drusen present under the retina and pigment changes in the retina – may cause some vision loss, but symptoms usually go unnoticed.
Late AMD: large drusen are present under the retina and vision loss occurs from damage to the macula.
- Dry AMD: breakdown of the light-sensitive cells in the macula and the supporting tissue, which cause vision loss.
- Wet AMD: abnormal, leaky blood vessels grow under the retina and can cause damage and swelling of the macula. This type of late AMD often progresses more rapidly than dry.
Risk Factors for Developing AMD
- Age: most likely to occur after the age of 60 years old
- Smoking: research has shown smoking doubles one’s risk of developing AMD
- Race: AMD is more common among Caucasians than African American or Hispanic/Latinos
- Family history: if you have a family history of AMD, you are at a higher risk for developing it
How is AMD Diagnosed?
AMD is diagnosed through a comprehensive eye exam performed by an optometrist or ophthalmologist. Some of the tests performed are:
- Visual acuity – measures one’s ability to see close up and far away
- Dilated eye exam – provides the optometrist with a better view of the back of your eye, specifically the macular region of the retina
- Amsler grids – the doctor may ask you to look at a chart composed of straight lines in a grid format. If the grid looks broken or wavy, it can indicate changes in the macula.
- Optical Coherence Tomography – using a specialized machine, light waves produce high-resolution images of the retina’s layers. This is a painless procedure done in-office. Patients place their chin on a rest, while a light beam obtains images of the eyes.
Treatment Options for AMD
Currently, there is no treatment for the early stages of AMD where vision loss is not present. Your eye care professional may recommend yearly monitoring as well as preventative measures such as exercising, avoiding smoking and eating specific foods such as leafy green vegetables and fish.
An Age-Related Eye Disease Study (AREDS) found those with intermediate or late AMD may benefit from taking a vitamin supplement containing ingredients such as vitamin C, E, zinc, copper, and beta-carotene. These supplements do not help cure the disease, but are thought to slow AMD’s progression.
For those with advanced wet AMD there are more invasive therapies to prevent further vision loss. These include:
- Injections into the eye of a drug, which blocks the growth of new blood vessels. The eye will be numbed and cleaned prior to the injection. Your optometrist may prescribe antibiotics to prevent infection. Injections typically occur a few times a month.
- Photodynamic therapy uses a laser to treat areas of the retina and stop further vision loss. A drug called verteporfin is injected into the arm and travels to the new blood vessels. The doctor can use the laser to activate the drug in the abnormal blood vessels, stopping their growth and the progressive vision loss, while not affecting the normal blood vessels.
- Laser surgery can be performed to destroy the abnormal blood vessels when they are limited to a small area of the eye. This therapy is a less common treatment option because it uses a strong laser that may destroy the surrounding healthy tissue, leaving a small blind spot in the eye. Though vision may be worse after surgery, it can help prevent more dramatic vision loss in the future.
Living with Vision Loss from AMD
There are numerous resources available for those who have experienced vision loss because of advanced AMD. It is important to work with your primary eye care provider as well as an optometrist or ophthalmologist who specializes in low vision. The Eye Institute (TEI) of Salus University has a department dedicated exclusively to providing vision rehabilitation and management techniques to those with low vision.
Low vision devices such as reading glasses with high-powered lenses, magnifiers, computer aids and other technologies can greatly improve quality of life for those with vision loss.
Only a comprehensive eye exam with an optometrist can properly address AMD. TEI has optometrists specially dedicated to treating all stages of AMD and providing customized management plans for each patient.