MACULAR DEGENERATION
The macula, a specialized part of the retina, gives us our ability to read and recognize colors. For reasons yet to be learned, the macula is particularly susceptible to a degenerative aging process known as macular degeration. Today, approximately 1.7 million older Americans have macular degeneration.
This picture simulates how the vision is affected by macular degeneration. Macular Degeneration is a vision problem of the retina or light sensitive layer of the eye in older individuals. Yellowish deposits called drusen form in the macula area of the eye, resulting in distortion and blurring of vision. In advanced cases, blind spots develop that grow larger as the disease progresses. This condition causes a loss of central vision in one or both eyes that can take place either gradually or suddenly. Macular degeneration does not cause total blindness. People with macular degeneration usually maintain peripheral (i.e. side) vision.
Types of Macular Degeneration
There are two types of macular degeneration, classified as "wet" and "dry." The most common form is the dry type. Wet occurs when blood vessels from beneath the retina leak blood, pushing on the light receptor cells and damaging the macula area.
DRY MACULAR DEGENERATION afftects the retina, the light sensitive layer of the eye. It typically begins with tiny deposits of a yellowish material known as "drusen" in the macula area. As these yellowish deposits form under the retina, they can result in distortion, blurring of vision and gradual vision loss of varying degrees. As the condition progresses, the macula becomes permanently thinned and scarred. There is no treatment for dry macular degeneration; however, recent research indicates that certain vitamin and mineral supplements decrease the progress of the disease. Research for viable treatment options is ongoing. In the meantime, use of magnifiers and other low vision adaptations should be investigated.
- View an animation demonstrating DRY macular degeneration using Windows Media Player.
- View an animation demonstrating DRY macular degeneration using Quick Time Player.
WET MACULAR DEGENERATION is a severe progression of the dry type. As more and larger deposits of drusen develop under the retina, larger areas of the macula are damaged. Blood vessels growing up from below the retina leak blood under the macula. These abnormal blood vessels may break and cause bleeding. Pressure from these pockets of blood damage the light sensing cells, detroying the ability to see straight ahead. Scars often form, further destroying the sensitive macular area. Wet (also called “neovascular”) macular degeneration is the more unusual and more severe form of macular degeneration, capable of causing sudden, rapid loss of vision.
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Neovascular, or wet, age-related macular degeneration |
Fundus photo showing neovascular, or wet, age-related macular degeneration |
While recent studies by the National Eye Institute have shown the effectiveness of laser and medical therapy in reducing the risk of severe vision loss, identification of the condition and its treatment must be initiated quickly. It is strongly suggested that people over 60 – particularly those who have lost vision in one eye for any reason – test their macular function every day.
How Macular Degeneration Affects Vision
In the early stages, lines that once appeared straight, such as door frames, curtain rods, or the edges of books, now appear curved. People may also notice early on that colors seem faded or gray, or that they are simply having difficulty seeing print clearly in one or both eyes. The faces of family members and friends appear blurred, and it becomes increasingly difficult to read signs or standard print.
Adopting the use of low vision aids such as magnifying lenses, appropriate auxiliary lighting, closed circuit television systems (CCTVs) and telescopic lenses can help people perform daily tasks. A wide selection of adaptive devices are available to loan from Cleveland Sight Center, or to purchase in the "EYE-dea" Shop or via "EYE-dea" Shop online. With the use of magnifiers, large print publications, and a number of other readily available vision aids, people can continue to read and do many other activities.
We also recommend a thorough rehabilitation assessment administered by one of Cleveland Sight Center’s doctors of optometry in the Low Vision Clinic. Cleveland Sight Center’s Low Vision Clinic specialists teach patients how to effectively use their remaining vision, as well as how to use prescribed optical aids, appropriate lighting techniques for glare control and contrast enhancement and correct use of a CCTV. In addition, they provide education about occular disease and teach rehabilitation skills.
How to Test
One simple test is to look at a geometrically patterned straight lined Amsler grid. You can also obtain this item, at no charge, at any eye doctor’s office. While covering each eye, one at a time, look for bending, distortion or blank spaces in the lines that are known to be straight. If you detect any abnormalities report them to your eye doctor immediately. As seen in the diagram below, the Amsler grid on the left represents normal vision. The Amsler grid on the right represents vision affected by macular degeneration.
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