Age-related macular degeneration (AMD) is the top cause of severe vision loss in people over the age of 50, according to the American Optometric Association.
While AMD does not cause completely blindness, it can cause the loss of sharp central vision used for activities like reading, seeing faces, cooking, or driving. Losing central vision makes it hard for someone to see fine details in nearby or faraway objects, but still have normal side vision.
Light carries visual information about the outside world into the eye through the pupil. Once inside the eye, the light strikes a light-sensitive layer of tissue lining the backside of the interior of the eye. This tissue, known as the retina, absorbs the light and converts the information carried on the light into impulses. The optical nerve carries the impulses to the brain, which converts the impulses into the visual images a person sees.
Age-related macular degeneration affects the macula, which is a small patch of specialized cells that sit near the center of the retina. The macula is the part of the eye that controls the sharpness of vision. It is responsible for all central vision, most of the color vision, and much of the fine detail a person sees. As its name suggests, age-related macular degeneration involves the degeneration, or breakdown, of the macula.
Symptoms of AMD
Age-related macular degeneration is a progressive disease, which means it gets worse over time. As AMD progresses, many people see a blurry area near the center of their vision. Over time, the blurry area gets bigger; blank spots may appear and objects may seem less bright than before. Straight lines can look wavy or crooked, and the shape of objects may appear distorted.
Types of AMD
There are two main types of macular degeneration: “dry” and “wet.”
In dry AMD, parts of the macula get thinner over time and the loss of central vision gets worse. Tiny clumps of protein, known as drusen, begin to grow beneath the retina. There is currently no way to treat dry AMD. About 80 percent of people with AMD have the dry form.
Wet AMD is a condition in which new abnormal blood vessels begin to grow beneath the retina. Blood or other fluids can leak from the abnormal blood vessels, which can scar the macula. Wet AMD is less common than dry AMD, but wet AMD is more serious and can lead to faster vision loss. Most people with wet AMD do not realize they have the condition until their vision is very blurry.
Risk Factors for AMD
Certain factors can increase the risk for AMD. These risk factors include:
- Eating a diet high in saturated fat, such as that found in meat, butter and cheese
- Being overweight
- Cigarette smoking
- Being over the age of 50
- High blood pressure
- Heart disease
- High blood cholesterol
- Family history of age-related macular degeneration
- Being Caucasian
Diagnosis and Treatment of Age-related Macular Degeneration
Eye doctors can check for age-related macular degeneration as part of a comprehensive eye exam. The eye test for AMD is simple and painless – it involves putting dilating eye drops into the eye to widen the pupil, which allows the eye doctor to use a special lens to look inside the eye for signs of AMD. The eye doctor may use other tests, such as an optical coherence tomography (OCT) scan that produces very detailed images of the retina and macula.
There is currently no treatment for the dry form of AMD. Eating eye-healthy foods, such as dark leafy greens, yellow fruits and vegetables, fish, and a balanced, nutrient-rich diet may help. An eye doctor may recommend vitamin supplements for some people with substantial drusen or serious vision loss. These supplements may include:
- Vitamin C (500 mg)
- Vitamin E (400 IU)
- Lutein (10 mg)
- Zeaxanthin (2 mg)
- Zinc (80 mg)
- Copper (2 mg)
Medications known as anti-VEGF drugs can help treat wet AMD. Anti-VEGF drugs helps reduce the number of abnormal blood vessels in the retina, and slows any leakage from those blood vessels. Eye doctors use a very thin needle to administer anti-VEGF drugs into the eye.
Laser surgery may be effective in some cases of wet AMD. The procedure involves shining a laser light beam onto the abnormal blood vessels, which reduces the number of blood vessels in the retina and slows their leaking.
For more information about ADM, contact Coldwater Vision Center.