Macular degeneration is the leading cause of vision loss, according to the American Macular Degeneration Foundation. About 10 million people in the United States have macular degeneration, which is more than glaucoma and cataracts combined.
HOW MACULAR DEGENERATION CAUSES VISION LOSS
Macular degeneration is an eye problem that affects the retina, which is the light-sensitive tissue on the inside back layer of the eye. The retina is responsible for capturing images, much like the film in a camera.
Specifically, macular degeneration affects the centermost portion of the retina, known as the macula, which allows the eye to detect fine detail. The macula contains millions of light-sensitive cells. Macular degeneration causes these macular cells to die, which destroys the individual’s sharp, central vision.
Age-related macular degeneration (AMD) is most likely to develop by the age of 60, according to the National Eye Institute, although a patient can develop the condition at an earlier age. AMD can develop quickly or quite slowly. It may affect one or both eyes. A blurred area in the center of vision is a common symptom as the condition progresses. The blurred area grows larger in time and blank spots in the patient’s central vision may occur. Some people with AMD notice that objects are not as bright as they once appeared.
By itself, macular degeneration does not lead to blindness, which is an inability to see. Instead, AMD causes loss of central vision – images appear blurry, dark or distorted. This makes reading, driving, cooking, seeing faces and other visual activities more difficult.
WHO IS AT RISK FOR MACULAR DEGENERATION?
Some people have a greater risk for developing macular degeneration. Age is a major risk factor for AMD. Other risk factors include:
- Smoking – Smokers face twice the risk for AMD
- Race – AMD is more common among Caucasians
- Family history of AMD – Medical scientists have identified at least 20 genes that affect the risk for developing AMD
Lifestyle choices may affect the development of AMD. Individuals may be able to reduce their risk for the vision problem by avoiding smoking, exercising regularly, and by maintaining a healthy blood pressure and blood cholesterol levels. A diet rich in fish and leafy green vegetables can also reduce the risk for developing macular degeneration.
HOW EYE DOCTORS DIAGNOSE MACULAR DEGENERATION
Macular degeneration often causes no symptoms in its early and intermediate stages – only an eye doctor can detect the condition in the earliest phases. To detect macular degeneration or AMD, an eye doctor performs a comprehensive eye exam that may include:
- Visual acuity test – to measure how well a patient sees at distances
- Dilated eye exam – the eye care professional uses eye drops to widen the pupils to make it easier to look for signs of macular degeneration
- Amsler grid – resembles graph paper; changes in vision makes straight grid lines appear wavy
- Fluorescein angiogram – imaging test that creates pictures of the blood vessels of the eyes
- Optical coherence tomography – another imaging test to create a picture of the retina
During these eye exams, the eye care professional looks for yellow deposits beneath the retina, known as drusen. While most people develop very small amounts of drusen as they age, a medium to large amount of drusen may by a sign of AMD.
Eye doctors also look for changes in pigment under the retina. There are pigmented cells in the iris, which is the colored part of the eye, but there are also pigmented cells beneath the retina. When these cells break down, they release pigment. In the early stages of the disease, an eye care professional may be able to see dark clumps of released pigment. Later, the vision specialist may see areas containing less pigmentation. Changes in retinal cell pigmentation do not affect the color of a person’s eyes.
TREATMENT FOR MACULAR DEGENERATION
While macular degeneration is treatable, it is not curable. This means treatment can slow vision loss but it cannot restore lost vision.
Certain treatments may slow the progression of AMD. Injections into the eye can block the development of new abnormal blood vessels associated with macular degeneration, for example. Laser surgery and photodynamic therapy are types of advanced treatments for AMD.
Individuals concerned about macular degeneration or who are at high risk for developing this condition should make an appointment with an eye care specialist.