Dry macular degeneration

Overview

Dry macular degeneration is an eye condition that causes blurred vision or reduced central vision. It is caused by the breakdown of a part of the retina known as the macula (MAK-u-luh). The macula is responsible for central vision. This condition is common among people over 50.

Dry macular degeneration may start in one eye then develop 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 side 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 caused by 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 care professional 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're over age 60.

Causes

No one knows exactly what causes dry macular degeneration. Research suggests that it may be a combination of genes and other 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 the risk of macular degeneration include:

• Age. This disease is most common in people over 50.
• Family history and genetics. This disease has a hereditary component, meaning it runs in families. Researchers have identified several genes linked to the condition.
• Race. Macular degeneration is more common in white people.
• Smoking. Smoking cigarettes or being exposed to tobacco smoke on a regular basis greatly increases the risk of macular degeneration.
• Obesity. Research suggests that obesity may increase the chance that early or intermediate macular degeneration will progress to the more serious form of the disease.
• Cardiovascular disease. If you have heart or blood vessel disease, called cardiovascular 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 complete 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 the 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 healthcare team's instructions for controlling the condition.
• Don't smoke. People who smoke are more likely to develop macular degeneration than are people who don't smoke. Ask a healthcare professional 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 antioxidant vitamins 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.

Diagnosis

An eye care professional may diagnose dry macular degeneration by reviewing medical and family history and doing a complete eye exam. Other tests may be done, including:

• Examination of the back of the eye. An eye doctor puts drops in the eyes to dilate them and uses a special tool to examine the back of the 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 the vision field. An Amsler grid may be used to test for changes in the center of the vision field. If you have macular degeneration, some of the straight lines in the grid may look faded, broken or distorted.
• Fluorescein angiography. During this test, an eye doctor injects a dye into a vein in the arm. The dye travels to and highlights the blood vessels in the eye. A special camera takes pictures as the dye travels through the blood vessels. The images may show retinal or blood vessel changes.
• 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 sections of the retina. It identifies areas of thinning, thickening or swelling. These can be caused by fluid buildup from leaking blood vessels in and under the retina.

Treatment

For now, there's no way to reverse damage from dry macular degeneration. However, there are many clinical trials in progress. If the condition is diagnosed early, you can take steps to help slow its progression, such as taking vitamin supplements, eating healthy and not smoking.

Vitamin supplements

For people with intermediate or advanced disease, taking a high-dose formulation of antioxidant vitamins and minerals may help reduce the risk of vision loss. Research from the Age-Related Eye Disease Study 2 (AREDS2) has shown benefit in a formulation that includes:

• 500 milligrams (mg) of vitamin C.
• 400 international units (IU) of vitamin E.
• 10 mg of lutein.
• 2 mg of zeaxanthin.
• 80 mg of zinc as zinc oxide.
• 2 mg of copper as cupric oxide.

The evidence doesn't show benefit in taking these supplements for people with early-stage dry macular degeneration. Ask your eye doctor if taking supplements is right for you.

Low vision rehabilitation

Age-related macular degeneration doesn't affect your side vision and typically doesn't cause total blindness. But it can reduce or eliminate central vision. You need central vision to read, drive and recognize people's faces. It may help for you to get care from a low vision rehabilitation specialist, an occupational therapist, your eye doctor and others trained in low vision rehabilitation. They can help you find ways to adapt to your changing vision.

Surgery to implant a telescopic lens

For some 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, has 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 useful in urban settings as an aid to see street signs.

Lifestyle and home remedies

Even after receiving a diagnosis of dry macular degeneration, these steps may help slow vision loss.

• Don't smoke. If you smoke, ask a healthcare professional for help quitting.

• Choose a healthy diet. The antioxidant vitamins in fruits and vegetables contribute to eye health. Kale, spinach, broccoli, squash and other vegetables have high levels of antioxidants, including lutein and zeaxanthin. These nutrients may benefit people with macular degeneration.

  Eating foods with high levels of zinc also may be helpful for people with macular degeneration. These include high-protein foods, such as beef, pork and lamb. Nonmeat sources include milk, cheese, yogurt, whole-grain cereals and whole-wheat bread.

  Another good choice is healthy unsaturated fat, such as in olive oil. And research studies have shown that a diet high in omega-3 fatty acids, such as in salmon, tuna and walnuts, may lower the risk of advanced age-related macular degeneration. But the same benefit is not shown from taking omega-3 supplements, such as fish oil pills.

• Manage your other medical conditions. If you have cardiovascular disease or high blood pressure, for example, take your medicine and follow your healthcare team's instructions for controlling the condition.
• 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.
• Have routine eye exams. Ask your eye doctor about the recommended schedule for follow-up exams. In between checkups, you can do a self-assessment of your vision using an Amsler grid. These steps will help tell you if your condition develops into wet macular degeneration, which can be treated with medicines.

Coping and support

These tips may help you cope with your changing vision:

• Get your eyeglass prescription checked. If you wear contacts or glasses, be sure your prescription is up to date. If new glasses don't help, ask for a referral to a low vision specialist.

• Use magnifiers. A variety of magnifying devices can help you with reading and other close-up work, such as sewing. Such devices include hand-held magnifying lenses or magnifying lenses you wear like glasses.

  You also may use a closed-circuit television system that uses a video camera to magnify reading material and project it on a video screen.

• Change your computer display and add audio systems. Adjust the font size in your computer's settings. And adjust your monitor to show more contrast. You also may add speech-output systems or other technologies to your computer.
• Use electronic reading aids and voice interfaces. Try large-print books, tablet computers and audiobooks. Some tablet and smartphone apps are designed to help people with low vision. And many of these devices now come with voice recognition features.
• Select special appliances made for low vision. Some clocks, radios, telephones and other appliances have extra-large numbers. You may find it easier to watch a television with a larger high-definition screen, or you may want to sit closer to the screen.
• Use brighter lights in your home. Better lighting helps with reading and other daily activities, and it may reduce the risk of falling.
• Consider your transportation options. If you drive, check with your doctor to see if it's safe to continue doing so. Be extra cautious in certain situations, such as driving at night, in heavy traffic or in bad weather. Use public transportation or ask family members to help, especially with night driving. Or use local van or shuttle services, volunteer driving networks, or ride-sharing.
• Get support. Having macular degeneration can be difficult, and you may need to make changes in your life. You may go through many emotions as you adjust. Consider talking to a counselor or joining a support group. Spend time with supportive family members and friends.

Preparing for an appointment

You likely will need a dilated eye exam to check for macular degeneration. Make an appointment for a complete eye exam with a doctor who specializes in eye care — an optometrist or an ophthalmologist.

What you can do

Before your appointment:

• When you make the appointment, ask if you need to do anything to prepare.
• List any symptoms you're experiencing, including those that seem unrelated to your vision problem.
• List all medicines, vitamins and supplements you take, including the doses.
• Ask a family member or friend to go with you. Having your pupils dilated for the eye exam will affect your vision for a time afterward, so you may need someone to drive or be with you after your appointment.
• List questions to ask your eye doctor.

For macular degeneration, questions to ask include:

• Do I have dry or wet macular degeneration?
• How advanced is my macular degeneration?
• Is it safe for me to drive?
• Will I experience further vision loss?
• Can my condition be treated?
• Will taking a vitamin or mineral supplement help prevent further vision loss?
• What's the best way to monitor my vision for any changes?
• What changes in my symptoms should I call you about?
• What low vision aids might be helpful to me?
• What lifestyle changes can I make to protect my vision?

What to expect from your doctor

Your eye doctor is likely to ask you a few questions, such as:

• When did you first notice your vision problem?
• Does the condition affect one or both eyes?
• Do you have trouble seeing things near to you, at a distance or both?
• Do you smoke or did you used to smoke? If so, how much?
• What types of foods do you eat?
• Do you have other medical conditions, such as high cholesterol, high blood pressure or diabetes?
• Do you have a family history of macular degeneration?