Age-related macular degeneration is a deterioration or breakdown of the macula. The macula is the central part of the retina, a thin layer of light sensitive tissue in the back of the eye. The macula allows you to see fine details clearly and perform activities such as reading and driving. When the macula doesn’t function correctly, your central vision can be affected by blurriness, dark areas or distortion. Macular degeneration affects your ability to see near and far, and can make some activities, like reading small print or threading a needle, difficult or impossible.
Although macular degeneration reduces vision in the central part of your vision, it does not affect the eye’s side or peripheral vision. For example, you could see the outline of a clock but not be able to tell what time it is. Macular degeneration alone does not usually result in total blindness. Even in more advanced cases, people continue to have some useful vision and are often able to take care of themselves. In many cases, macular degeneration’s impact on your vision can be minimal.
Macular Degeneration Causes
There are different kinds of macular problems, but the most common is age-related macular degeneration. Exactly how it develops is not fully understood, but many factors such as your genetics, inflammation and environmental factors are thought to play a role. Macular degeneration is the leading cause of severe vision loss in people over 65.
Many people do not realize that they have a macular problem until blurred vision becomes obvious. Your doctor can detect early stages of macular degeneration during a medical eye examination that includes the following:
- An Amsler grid vision test in which you look at a chart that resembles graph paper.
- Viewing the macula with an ophthalmoscope.
- Sometimes special photographs of the eye, such as optical coherence tomography (OCT) and fluorescein angiographs, are taken to find abnormal blood vessels under the retina. With fluorescein angiographs, a fluorescent dye is injected into a vein in your arm and your eye is photographed as the dye passes through the blood vessels in the back of the eye.
What are the common types of macular degeneration?
The two main categories of age-related macular degeneration are ‘dry’ (atrophic) and ‘wet’ (exudative):
‘Dry’ or Atrophic Macular Degeneration
Most people have the ‘dry’ form of macular degeneration. It is caused by aging and thinning of the tissues of the macula. Vision loss is usually gradual.
‘Wet’ or Exudative Macular Degeneration
The ‘wet’ form of macular degeneration accounts for about 10% of all macular degeneration cases. It results when abnormal blood vessels form underneath the retina at the back of the eye. These new, abnormal blood vessels leak fluid or blood and blur central vision. Vision loss may be rapid and severe.
Macular Degeneration Symptoms
Macular degeneration can cause different symptoms in different people. The condition may be hardly noticeable in its early stages. Sometimes only one eye loses vision while the other eye continues to see well for many years. But when both eyes are affected, the loss of central vision may be noticed more quickly. The following are some common ways vision loss is detected:
- Words on a page or faces look blurred
- An empty area appears in the center of vision
- Straight lines look distorted
Macular Degeneration Treatments
Despite ongoing medical research, there is no cure yet for ‘dry’ macular degeneration. Based on clinical studies, some nutritional supplements may slow progression of macular degeneration. This is based on the Age Related Eye Disease Study (AREDS) that showed that a certain formula of vitamin A, vitamin C, vitamin E, zinc and copper reduced the chance of progression from intermediate to late stages of macular degeneration by about 25%. Treatment of advanced forms of ‘dry’ macular degeneration focuses on helping a person find ways to cope with visual impairment.
The most frequently used treatment for ‘wet’ macular degeneration is injection of a medicine that halts new blood vessel growth and causes them to regress. Despite advanced medical treatment, however, many people with age-related macular degeneration still experience some vision loss.
Occasionally, ‘wet’ macular degeneration can be treated with other procedures, including laser surgery. It may also be treated with photodynamic therapy (PDT), in which a light activated chemical is injected into the blood stream and activated in the eye with a low energy laser.
To help you adapt to lower vision levels, your doctor can prescribe optical devices or refer you to a low-vision specialist or center. A wide range of support services and rehabilitation programs are also available to help people with macular degeneration maintain a satisfying lifestyle. Because side vision is usually not affected, a person’s remaining sight is very useful. Often, people can continue with many of their favorite activities by using low-vision optical devices such as magnifying devices, closed-circuit television, large-print reading materials, and talking computerized devices.
Visit the American Academy of Ophthalmology’s webpage on Macular Degeneration.