Macular degeneration (patient information)
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What is macular degeneration?
Macular degeneration is an eye disorder that damages the macula, which is responsible for central vision and is located near the center of the retina. The disease gradually destroys sharp, central vision, thereby making it difficult to see fine details. Because it normally affects older adults, the disorder is also called age related macular degeneration. According to the American Academy of Ophthalmology, it is the leading cause of central vision loss in the United States today for those over the age of fifty years.[1]
Although macular degeneration typically affects older adults, Stargardt’s disease (STGD), also known as Juvenile Macular Degeneration, is an autosomal recessiveretinal disorder characterized by a juvenile-onset macular dystrophy, alterations of the peripheral retina, and subretinal deposition of lipofuscin-like material.
Macular degeneration occurs in two forms: dry and wet.
- Dry macular degeneration occurs when the blood vessels under the macula become thin and brittle. Small yellow deposits, called drusen, form under the macula. As these drusen increase in size and number, they create a blurred and dim spot in the central vision of the eye. Almost all people with macular degeneration start with the dry form. It has three stages, all of which may occur in one of both eyes:
- Early dry macular degeneration
- Intermediate dry macular degeneration
- Advanced dry macular degeneration
- Wet macular degeneration occurs when abnormal blood vessels behind the retina start to grow under the macula. This is called choroidal neovascularization. These new blood vessels tend to be very fragile and often leak blood and fluid. The blood and fluid raise the macula from its normal place at the back of the eye, which leads to rapid damage of the macula. Although only about 10 percent of people with macular degeneration have this form, it causes most of the vision loss associated with the condition. With wet macular degeneration, loss of central vision can occur quickly, and there are no stages.
All people who have the wet form had the dry form first. Both the wet form and the advanced dry form are considered advanced macular degeneration, and vision loss occurs with either form.
What are the symptoms of macular degeneration?
At first there may not be any symptoms. However, as the disease progresses, central vision may be affected. It is very important to note that macular degeneration typically does not affect side (peripheral) vision, meaning patients will not have complete vision loss from this disease. Although specific symptoms vary by whether the form is dry or wet, both forms cause no pain.
More detailed symptoms by type include:
- Dry macular degeneration: The most common early sign is blurred vision in the center of the field of vision. As fewer cells in the macula are able to function, people will see details less clearly in front of them. Often objects in the central vision look distorted and dim, and colors look faded. Often this blurred vision will go away in brighter light. A patient may have trouble reading print or seeing other details, but can generally see well enough to walk and perform most routine activities. If the loss of these light-sensing cells becomes great, people may see a small, but growing, blind spot in the middle of their field of vision. In the later stages, patients may not be able to recognize faces until people are close to them. Dry macular degeneration generally affects both eyes, but vision can be lost in one eye while the other eye seems unaffected.
- Wet macular degeneration: The classic early symptom is that straight lines appear distorted and wavy. This results when fluid from the leaking blood vessels gathers and lifts the macula, distorting vision. A small blind spot may also appear in wet macular degeneration, resulting in loss of one's central vision. Central vision loss can occur very quickly. If this occurs, the patient urgently need evaluation by an ophthalmologist with experience in retina disease.
What are the causes of macular degeneration?
Macular degeneration is caused by damage to the area around blood vessels that supply the macula. Although scientists are not sure what causes this to happen, the change in the blood vessels is what damages the macula.
Who is at risk for macular degeneration?
The greatest risk factor is age. Although macular degeneration may occur during middle age, studies show that people over age 60 are clearly at greater risk than other age groups. For instance, a large study found that people in middle-age have about a 2% risk of getting macular degeneration, but this risk increased to nearly 30% in those over age 75.
Other risk factors include:
- Smoking: Smoking may increase the risk of macular degeneration.
- Obesity: Research studies suggest a link between obesity and the progression of early and intermediate stage macular degeneration to advanced macular degeneration.
- Race: Whites are much more likely to lose vision from macular degeneration than African Americans.
- Family history: Those with immediate family members who have macular degeneration are at a higher risk of developing the disease.
- Gender: Women appear to be at greater risk than men.
- Diet: Diets high in fat may increase the risk of macular degeneration
How to know you have macular degeneration?
If you are over age 60 and you have had changes in vision, your eye care provider will do an examination. During the exam, the doctor will use drops to enlarge (dilate) your pupils, and a special lens to view your retina and optic nerve.
The doctor will look for changes in the blood vessels and the membrane that surrounds them. This may show drusen, the yellow deposits that form on this membrane in dry macular degeneration.
You may be asked to cover one eye and look at a pattern of lines called an Amsler grid. If the straight lines appear wavy, it may be a sign of macular degeneration.
Other tests for macular degeneration may include:
When to seek urgent medical care
If you have macular degeneration, your eye care provider may recommend that you check your vision every day on an Amsler grid. Call your provider immediately if the lines appear wavy, or you notice any other changes in your vision.
Treatment options
Dry macular degeneration
Once dry macular degeneration reaches the advanced stage, no form of treatment can prevent vision loss. However, a combination of vitamins, antioxidants, and zinc may slow the disease from progressing to the advanced stage. Slowing macular degeneration's progression from the intermediate stage to the advanced stage will save the vision of many people. This combination of vitamins is often called the "AREDS" formula, as it was The National Eye Institute's Age-Related Eye Disease Study (AREDS) that discovered it.
The recommended supplements are for non-smokers. The dosage of the AREDS formulation is:
- 500 milligrams of vitamin C
- 400 International Units of vitamin E
- 15 milligrams of beta-carotene (often labeled as equivalent to 25,000 International Units of vitamin A)
- 80 milligrams of zinc
- 2 milligrams of copper
Wet macular degeneration
Wet macular degeneration can be treated with laser surgery, photodynamic therapy, and injections into the eye. None of these treatments is a cure for wet macular degeneration. The disease and loss of vision may progress despite treatment.
- Laser surgery: This procedure uses a laser to destroy the fragile, leaky blood vessels. A high energy beam of light is aimed directly onto the new blood vessels and destroys them, preventing further loss of vision. However, laser treatment may also destroy some surrounding healthy tissue and some vision. Only a small percentage of people with wet macular degeneration can be treated with laser surgery. Laser surgery is more effective if the leaky blood vessels have developed away from the fovea, the central part of the macula. Laser surgery is performed in a doctor's office or eye clinic.
The risk of new blood vessels developing after laser treatment is high. Repeated treatments may be necessary. In some cases, vision loss may progress despite repeated treatments.
- Photodynamic therapy: A drug called verteporfin is injected into your arm. It travels throughout the body, including the new blood vessels in your eye. The drug tends to "stick" to the surface of new blood vessels. Next, a light is shined into your eye for about 90 seconds. The light activates the drug. The activated drug destroys the new blood vessels and leads to a slower rate of vision decline. Unlike laser surgery, this drug does not destroy surrounding healthy tissue. Because the drug is activated by light, you must avoid exposing your skin or eyes to direct sunlight or bright indoor light for five days after treatment.
Photodynamic therapy is relatively painless. It takes about 20 minutes and can be performed in a doctor's office.
Photodynamic therapy slows the rate of vision loss. It does not stop vision loss or restore vision in eyes already damaged by advanced macular degeneration. Treatment results often are temporary, so the patient may need to be treated again.
- Injections: Wet macular degeneration can now be treated with new drugs that are injected into the eye (anti-angiogenesis, anti-VEGF therapy) -- drugs such as bevacizumab (Avastin) and ranibizumab (Lucentis)). Abnormally high levels of a specific growth factor occur in eyes with wet macular degeneration and promote the growth of abnormal new blood vessels. This drug treatment blocks the effects of the growth factor.
You will need multiple injections that may be given as often as monthly. The eye is numbed before each injection, so this is a painless process. After the injection, you will remain in the doctor's office for a while and your eye will be monitored. This drug treatment can help slow down vision loss from macular degeneration and in some cases improve sight.
Additionally, low-vision aids (such as special lenses) and therapy can help you use the vision that you have more effectively, and improve your quality of life.
Where to find medical care for macular degeneration
Directions to Hospitals Treating macular degeneration
Prevention of macular degeneration
Although nothing can be to avoid certain risk factors for macular degeneration (e.g. race, sex, genetics), certain lifestyle changes can be made to help prevent the onset of the disease. These include:
- Eat a healthy diet high in green leafy vegetables and fish.
- Do not smoke.
- Maintain a normal blood pressure.
- Keep your cholesterol within a healthy range.
- Watch your weight.
- Exercise.
- Limit excessive exposure to sunlight.
What to expect (Outlook/Prognosis)
Most people with mild dry macular degeneration will not have disabling central vision loss. However, there is no way to predict who will progress to a more severe form of the disease.
The wet form of macular degeneration often leads to significant vision loss.
Although macular degeneration can cause people to lose the ability to read, drive a car, and recognize faces that are not very close-up, it never causes complete blindness. This disorder results in the loss of central vision only -- macular degeneration cannot cause peripheral vision loss.
Nearly everyone with macular degeneration can get around, eat, perform personal hygiene, and do other routine activities without too much difficulty.
Sources
http://www.nlm.nih.gov/medlineplus/ency/article/001000.htm
http://www.nei.nih.gov/health/maculardegen/armd_facts.asp
- ↑ de Jong PT (2006). "Age-related macular degeneration". N Engl J Med. 355 (14): 1474–1485. PMID 17021323.