Dry macular degeneration is a common eye disorder among people over 50. It causes blurred or reduced central vision due to the breaking down of the inner layers of the macula (MAK-u-luh), the part of the retina that gives the eye clear vision in the direct line of sight.
Dry macular degeneration may start in one eye before developing in the other eye. It also may develop in both eyes at the same time. Over time, vision may worsen and affect the ability to do things, such as read, drive and recognize faces. But having dry macular degeneration doesn't mean you'll lose all your sight. Vision loss is typically central, and people retain their peripheral vision. Some people have only mild central vision loss. In others, it can be more severe.
Early detection and self-care measures may delay vision loss due to dry macular degeneration.
Symptoms
Dry macular degeneration symptoms usually develop gradually and without pain. They may include:
• Visual distortions, such as straight lines seeming bent
• Reduced central vision in one or both eyes
• The need for brighter light when reading or doing close-up work
• Increased difficulty adapting to low light levels, such as when entering a dimly lit restaurant or theater
• Increased blurriness of printed words
• Difficulty recognizing faces
• A well-defined blurry spot or blind spot in the field of vision
Dry macular degeneration can affect one or both eyes. If only one eye is affected, you may not notice any changes in your vision. This is because your good eye may compensate for the affected eye, and the condition doesn't affect the side vision, so it does not cause total blindness.
Dry macular degeneration is one of two types of age-related macular degeneration. It can progress to wet macular degeneration, which is when blood vessels grow and leak under the retina. The dry type is more common, but it usually progresses slowly over years. The wet type is more likely to cause a relatively sudden change in vision resulting in serious vision loss.
When to see a doctor
See your eye doctor if:
• You notice changes, such as distortion or blind spots, in your central vision
• You lose the ability to see fine detail
These changes may be the first sign of macular degeneration, particularly if you are over age 60.
No one knows exactly what causes dry macular degeneration. Research indicates that it may be a combination of family genes and environmental factors, including smoking, obesity and diet.
The condition develops as the eye ages. Dry macular degeneration affects the macula. The macula is the area of the retina that's responsible for clear vision in the direct line of sight. Over time, tissue in the macula may thin and lose cells responsible for vision.
Risk factors
Factors that may increase your risk of macular degeneration include:
• Age: This disease is most common in people over 60.
• Family history and genetics: This disease has a hereditary component. Researchers have identified several genes linked to the condition.
• Race: Macular degeneration is more common in white people.
• Smoking: Smoking cigarettes or being regularly exposed to tobacco smoke greatly increases your risk of macular degeneration.
• Obesity: Research indicates that being obese may increase your chance that early or intermediate macular degeneration will progress to the more severe form of the disease.
• Cardiovascular disease: If you have heart or blood vessel disease, you may be at higher risk of macular degeneration.
Complications
People whose dry macular degeneration has progressed to central vision loss have a higher risk of depression and social isolation. With profound loss of vision, people may see visual hallucinations. This condition is called Charles Bonnet syndrome. Dry macular degeneration may progress to wet macular degeneration, which can quickly cause vision loss if left untreated.
Prevention
It's important to have routine eye exams to identify early signs of macular degeneration. The following measures may help reduce your risk of developing dry macular degeneration:
• Manage all medical conditions. For example, if you have cardiovascular disease or high blood pressure, take your medicine and follow your health care provider's instructions for controlling the condition.
• Don't smoke. Smokers are more likely to develop macular degeneration than are nonsmokers. Ask your provider for help stopping smoking.
• Maintain a healthy weight and exercise regularly. If you need to lose weight, reduce the number of calories you eat and increase the amount of exercise you get each day.
• Choose a diet rich in fruits and vegetables. These foods contain that reduce your risk of developing macular degeneration.
• Include fish in your diet. Omega-3 fatty acids, which are found in fish, may reduce the risk of macular degeneration. Nuts such as walnuts also contain omega-3 fatty acids.
Your eye doctor may diagnose your condition by reviewing your medical and family history and conducting a complete eye exam. Other tests may be performed, including:
• Examination of the back of your eye. Your eye doctor puts drops in your eyes to dilate them and uses a special instrument to examine the back of your eye. The eye doctor looks for a mottled appearance that's caused by yellow deposits that form under the retina, called drusen. People with macular degeneration often have many drusen.
• A test for changes in the center of your vision. During an eye examination, your eye doctor may use an Amsler grid to test for changes in the center of your vision. If you have macular degeneration, some of the straight lines in the grid may look faded, broken or distorted.
• Fluorescein angiography. During this test, your eye doctor injects a dye into a vein in your arm. The dye travels to and highlights the blood highlights the blood vessels in your eye. A special camera takes several pictures as the dye travels through the blood vessels. The images will show if you have retinal or blood vessel changes, which are a sign of wet macular degeneration.
• Indocyanine green angiography. Like fluorescein angiography, this test uses an injected dye. It may be used alongside a fluorescein angiogram to identify specific types of macular degeneration.
• Optical coherence tomography. This noninvasive imaging test displays detailed cross-sectional images of the retina. It identifies areas where the retina may be thinning, thickening or swelling. These can be caused by fluid buildup from leaking blood vessels in and under your retina.
Treatment
For now, there's no way to reverse damage from dry macular degeneration, however, there are many clinical trials in progress. If your condition is diagnosed early, you can take steps to help slow its progression, such as taking vitamin supplements, eating healthy and not smoking.
Surgery to implant a telescopic lens
For selected people with advanced dry macular degeneration in both eyes, an option to improve vision may be surgery to implant a telescopic lens in one eye. The telescopic lens, which looks like a tiny plastic tube, is equipped with lenses that magnify your field of vision. The telescopic lens implant may improve both distance and close-up vision, but it has a very narrow field of view. It can be particularly useful in an urban environment to aid in identifying street signs.
Here is to your good health, Cathy
