The macula lutea is the yellow oval spot at the center of the retina (back of the eye). It is responsible for sharp, detailed central vision (also called visual acuity).

Macula

Fay A. Diseases of the visual system. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 449.

Age-related macular degeneration (AMD) is an eye disease that gradually destroys sharp central vision. It occurs in two formswet and dry. Although they may still have some vision, individuals afflicted with more advanced forms of the disease are often considered legally blind because their central vision is too blurred to accomplish tasks such as driving or reading. AMD, in either form, causes no pain.

Dry macular degeneration occurs when light-sensitive cells in the macula break down, causing blurred central vision. The macula is located on the retina, the light-sensitive region at the back of the eye that converts light into electrical impulses. Dry AMD is the more common form of the disease. In addition to blurring, another early signal of the disease is the presence of drusen. These yellow deposits under the retina do not cause AMD, however their presence indicates a greater chance of developing advanced dry of wet AMD. Dry AMD has three stages, characterized by an increasing number of drusen in each as well as worsening of vision. Advanced AMD is characterized by a breakdown of light-sensitive cells in tissue surrounding the retina.

The growth of abnormal blood vessels behind the retina and under the macula causes wet AMD. Often, these blood vessels are fragile, leaking blood and fluid. Damage occurs quickly as blood and fluid cause the macula to be raised from its normal place within the eye. Unlike dry AMD, there are no stages of progression with wet AMD.Seeing wavy lines are an early symptom of wet AMD. A small blind spot, obstructing central vision, may also rapidly occur.

The exact cause of AMD is unknown. The condition develops, however, as the eye ages. AMD is found most frequently in individuals over 60 years of age, although it can occur earlier. A family history of AMD also increases risk. Other factors that increase the risk of AMD are being Caucasian and female, smoking, obesity, high blood pressure, high cholesterol and a diet low in fruits and vegetables.

A comprehensive eye exam that includes visual acuity, dilation and tonometry can detect AMD.

Macular degeneration is an eye disorder that damages the center of the retina, which is called the macula. This makes it difficult to see fine details.

Age-related macular degeneration (ARMD); AMD; senile macular degeneration (SMD) is an older name that is no longer in common use.

The retina is the layer of tissue at the back of the inner eye. It changes light and images that enter the eye into nerve signals that are sent to the brain. The macula is the part of the retina that makes our vision sharper and more detailed.

Macular degeneration is caused by damage to the area around blood vessels that supply the macula. This change in the blood vessels damages the macula.

Two phases of macular degeneration (AMD) exist:

• 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.
• Wet macular degeneration occurs in only about 10% of people with macular degeneration. Brittle vessels break down and new abnormal and very fragile blood vessels grow under the macula. This is called choroidal neovascularization. These vessels leak blood and fluid, which leads to 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.

Scientists aren't sure what causes AMD. The disease is most common in people over 60, which is why it is often referred to as age-related macular degeneration.

In addition to heredity, other risk factors are:

• Caucasian race
• Cigarette smoking
• High-fat diet
• Female gender
• Obesity

At first you may not have symptoms. As the disease progresses, your central vision may be affected.

The most common symptom in dry AMD is blurred vision. This is limited to the center of the field of vision. Often objects in the central vision look distorted and dim, and colors look faded. A patient may have trouble reading print or seeing other details, but can generally see well enough to walk and perform most routine activities.

As the disease becomes worse, you may need more light to read or perform everyday tasks. The blurred spot in the center of vision gradually gets larger and darker. In the later stages, you may not be able to recognize faces until people are close to you.

AMD typically does not affect side (peripheral) vision. This is very important, because it means you will never have complete vision loss from this disease.

The most common early symptom of wet macular degeneration is that straight lines appear distorted and wavy. You may also notice a small dark spot in the center of your vision that gradually gets larger. Central vision loss can occur very quickly. If this occurs, you urgently need evaluation by an ophthalmologist with experience in retina disease.

If you are over age 60 and you've 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 AMD.

Other tests for macular degeneration may include:

• Fluorescein angiogram
• Optical Coherence Tomography (OCT)

No treatment exists for dry macular degeneration. However, a combination of vitamins, antioxidants, and zinc may slow the progression of the disease. This combination of vitamins is often called the "AREDS" formula. Smokers should not use this treatment.

The recommended supplements contain:

• 500 milligrams of vitamin C
• 400 international units of beta-carotene
• 80 milligrams of zinc
• 2 milligrams of copper

Although there is no cure for wet AMD, treatments may include:

• Laser surgery (laser photocoagulation) -- a small beam of light destroys the abnormal blood vessels.
• Photodynamic therapy -- a light activates a drug that is injected into your body to destroy leaking blood vessels.
• Special medications that slow the formation of new blood vessels in the eye (anti-angiogenesis, anti-VEGF therapy) -- drugs such as bevacizumab (Avastin) and ranibizumab (Lucentis) are injected into the eye to stabilize or improve vision. This is a painless process.

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.

AMD Alliance International -- (877) AMD-7171 -- www.amdalliance.org.

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, 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.

Loss of central vision may interfere with many daily activities, such as reading, working on the computer, or driving. You may need extra light or magnification to perform many of your normal activities.

If you have AMD, your health 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.

Although there is no known way to prevent macular degeneration, lifestyle factors can reduce your risk of developing the condition:

• Don't smoke
• Eat a healthy diet that is high in fruits and vegetables and low in animal fat
• Exercise regularly
• Maintain a healthy weight

See your eye care professional regularly for dilated eye exams.

American Academy of Ophthalmology Preferred Practice Pattern in Macular Degeneration.

The Age-Related Eye Disease Study (AREDS).

Gohel PS, Mandava N, Olson JL, Durairaj VD. Age-related macular degeneration: an update on treatment. Am J Med. 2008;121(4):279-281.

Martidis A, Tennant MTS. Age-related macular degeneration. In: Yanoff M, Duker JS, Augsburger JJ, et al., eds. Ophthalmology. 2nd ed. Philadelphia, Pa: Mosby Elsevier; 2004:chap 125.

[The colored part of the eye: brown, green, blue, etc. ... is called the macula,]

The macula is a small spot in the back of the eye, and not visible from the outside without instruments. The visible part around the pupil is the iris.

Macular degeneration is an eye disorder that slowly destroys sharp, central vision. This makes it difficult to see fine details and read.

The disease is most common in people over age 60, which is why it is often called age-related macular degeneration (ARMD, or AMD).

Age-related macular degeneration (ARMD); AMD; senile macular degeneration (SMD) is an older name that is no longer in common use.

The retina is at the back of the eye. It changes light and images that enter the eye into nerve signals that are sent to the brain. A part of the retina called the macula makes vision sharper and more detailed.

AMD is caused by damage to the blood vessels that supply the macula. This change also harms the macula.

There are two types of AMD:

• Dry AMD occurs when the blood vessels under the macula become thin and brittle. Small yellow deposits, called drusen, form. Almost all people with macular degeneration start with the dry form.
• Wet AMD occurs in only about 10% of people with macular degeneration. New abnormal and very fragile blood vessels grow under the macula. This is called choroidal neovascularization. These vessels leak blood and fluid. This form causes most of the vision loss associated with the condition.

Scientists are not sure what causes AMD. The condition is rare before age 55. It is most often seen in adults 75 years or older.

In addition to heredity, other risk factors are:

• Caucasian race
• Cigarette smoking
• High-fat diet
• Female gender
• Obesity

You may not have any symptoms at first. As the disease gets worse, you may have problems with your central vision.

SYMPTOMS OF DRY AMD:

The most common symptom in dry AMD is blurred vision. Often objects in the central vision look distorted and dim, and colors look faded. You may have trouble reading print or seeing other details, but you can generally see well enough to walk and perform most routine activities.

As the disease becomes worse, you may need more light to read or perform everyday tasks. A blurred spot in the center of vision gradually gets larger and darker.

In the later stages, you may not be able to recognize faces until they are close.

SYMPTOMS OF WET AMD:

The most common early symptom of wet AMD is that straight lines appear distorted and wavy.

There may be a small dark spot in the center of vision that gets larger over time.

Central vision loss can occur very quickly. If this occurs, you will need urgent evaluation by an ophthalmologist with experience in retinal disease.

You will have an eye exam. Drops will be placed into your eyes to widen (dilate) your pupils. The eye doctor will use special lenses to view your retina, blood vessels, and optic nerve.

The eye doctor will look for specific changes in the macula and blood vessels. One of the earliest findings in dry AMD are yellow deposits in the macula, called drusen.

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 AMD.

Other tests that may be done include:

• Fluorescein angiogram
• Fundus photography
• Optical coherence tomography (OCT)

If you have advanced or severe dry AMD, no treatment can restore your vision.

If you have early AMD and do not smoke, a combination of certain vitamins, antioxidants, and zinc may prevent the disease from getting worse. But it cannot give you back any vision that is already lost.

The combination is often called the "AREDS" formula. The recommended supplements contain:

• 500 milligrams of vitamin C
• 400 international units of beta-carotene
• 80 milligrams of zinc
• 2 milligrams of copper

Only take this vitamin combination if your doctor recommends it. Make sure your doctor knows about any other vitamins or supplements you are taking. Smokers should NOT use this treatment.

AREDS may also benefit you if you have a a family history and risk factors for AMD.

The supplements lutein and zeaxanthin may also be helpful, although they are not part of the AREDS formula.

If you have wet AMD, your doctor may recommend:

• Laser surgery (laser photocoagulation) -- a small beam of light destroys the leaking, abnormal blood vessels.
• Photodynamic therapy -- a light activates a drug that is injected into your body to destroy leaking blood vessels.
• Special medications that prevent new blood vessels from forming in the eye (anti-angiogenesis, anti-VEGF therapy) -- drugs such as bevacizumab (Avastin) and ranibizumab (Lucentis) are injected into the eye. This is a painless process.

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.

Close follow-up with your eye doctor is important.

• For dry AMD, a complete eye exam should be performed by an eye specialist at least once a year.
• People who have been treated for wet AMD need frequent, perhaps monthly, follow-up visits.

In AMD, early detection of vision changes is very important. Early detection leads to earlier treatment and often, a better outcome.

The best way to detect changes is by self-testing at home with an eye chart, called an Amsler grid. Test each eye individually with the vision correction you normally wear for reading.

AMD Alliance International -- (877) AMD-7171 -- www.amdalliance.org.

AMD typically does not affect side (peripheral) vision. This is very important, because it means complete vision loss never occurs from this disease. This disorder results in the loss of central vision only.

Mild, dry AMD usually does not cause disabling central vision loss. However, there is no way to predict who will develop a more severe form of the disease.

Wet AMD often leads to significant vision loss.

In general, macular degeneration can cause you to lose the ability to read, drive a car, and recognize faces at a distance. Most people with this eye disease are able to eat, bathe, and perform other regular tasks without too much difficulty.

This condition may make it hard to read, work on the computer, or drive. You may need extra light or magnification to do many of your normal activities.

If you have AMD, your health 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.

Although there is no known way to prevent macular degeneration, lifestyle factors can reduce your risk of developing the condition:

• Don't smoke
• Eat a healthy diet that is high in fruits and vegetables and low in animal fat
• Exercise regularly
• Maintain a healthy weight

See your eye care professional regularly for dilated eye exams.

Benson WE. Acquired macular disease. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 15th ed. Philadelphia, Pa: Lippincott Williams & Wilkins;2011:chap 23.

Yanoff M, Cameron D. Diseases of the visual system. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 431.

Review Date: 09/16/2011

Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.