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Adult Macular Degeneration by Heather S. Oliff, PhD

En Español (Spanish Version) More InDepth Information on This Condition

Definition

The retina is the tissue that lines the back of the eye. It sends visual signals to the brain. The macula is part of the retina. It is responsible for central vision. Macular degeneration is decline of the macula. It causes a gradual loss of sharp, central vision. The condition is mainly a disease of aging. In rare cases, it can occur in younger people.

Macular Degeneration

There are two types of adult (or age-related) macular degeneration (AMD):

Dry AMD—This occurs when an area of the retina becomes diseased. This leads to a slow breakdown of cells in the macula. The central vision is gradually lost. Dry AMD accounts for the majority of cases (90%).
Wet AMD—As dry AMD worsens, new blood vessels may begin to grow. These new blood vessels often leak blood and fluid under the macula. This can lead to permanent damage of the macular region. Wet AMD occurs in only 10% of the people with AMD. It accounts for the majority of blindness from this disease.

Causes

The cause of AMD is not known.

Risk Factors

Factors that increase your risk for AMD include:

Age: risk increases with age (most commonly seen in senior citizens)
Family members with AMD
Race: White
Smoking
Sex: women (possible increased risk)
Cardiovascular risks: high blood pressure , high cholesterol

Symptoms

In some people, AMD advances very slowly. It has little effect on their vision. In others, the disease progresses faster. It may lead to significant vision loss. Both dry and wet AMD cause no pain.

Symptoms include:

Blurred vision
Difficulty seeing details in front of you, such as faces or words in a book
Blurred vision that goes away in brighter light
A small, but growing blind spot in the middle of the field of vision
Straight lines (eg, door frames) appear crooked or distorted

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done. The doctor may suspect AMD if you are older and have had recent changes in your central vision. A specialist will look for signs of the disease. The doctor will use eye drops to dilate (enlarge) your pupils. This will allow a view of the back of the eye.

You may also be asked to view an Amsler grid. This is a pattern that looks like a checkerboard. Changes in your central vision will cause the grid to appear distorted. This is a sign of AMD.

Treatment

Treatment may include:

Dry AMD

Research has shown that certain high-dose vitamins and minerals may slow the progression of the disease in some people.

Wet AMD

Laser Photocoagulation

This procedure is used in some cases of wet AMD. A strong laser light beam is aimed onto the new blood vessels. The beam will destroy the vessels. It usually takes less than 30 minutes to complete. You may need additional laser treatments. This treatment is used less often since the development of newer treatments.

Photodynamic Therapy

This procedure is a type of treatment that involves injecting a light-sensitive dye into the blood. The affected areas in the back of the eye are then hit with a special laser light. The light activates the dye to destroy certain blood vessels. It also takes less than 30 minutes. You may need to have additional treatments.

Vascular Endothelial Growth Factor Inhibitor

Another way to treat wet AMD is an injection of a special medicine. It is called a vascular endothelial growth factor (VEGF) inhibitor. The medicine is injected into the vitreous (fluid) in the back of the eye. This method is quickly growing in popularity. It usually needs to be repeated multiple times. About 1/3 of patients show significant improvement in vision.

Prevention

There are no guidelines for preventing AMD. For overall eye health:

Have regular eye exams. The exam should include dilation to closely look at the retina.
If you smoke, quit .
Consider taking a multivitamin with antioxidants every day.
Consider omega-3 fatty acid supplements.

If you have AMD, your doctor may advise you to monitor for problems by using an Amsler grid at home. Your ophthalmologist should discuss the various treatment options with you.

RESOURCES:

American Macular Degeneration Foundation http://www.macular.org/
Macular Degeneration Foundation http://www.eyesight.org/

CANADIAN RESOURCES:

AMD Canada http://www.amdalliance.org/
The National Coalition for Vision Health http://www.visionhealth.ca/

References:

Age-related macular degeneration. National Eye Institute website. Available at: http://www.nei.nih.gov/health/maculardegen/index.asp . Accessed July 20, 2009.
Liew G, Mitchell P, Gillies MC, et al. Ranibizumab for neovascular age-related macular degeneration. N Engl J Med . 2006;355:1419-1431.
Macular Degeneration Foundation website. Available at: http://www.eyesight.org . Accessed July 20, 2009.
National Eye Institute website. Available at: http://www.nei.nih.gov/ . Accessed July 20, 2009.
Photodynamic therapy: an emerging treatment for classically leaky neovascularizations. Macular Degeneration Foundation website. Available at: http://www.eyesight.org/Research/Research-Photodynamic/research-photodynamic.html . Accessed July 20, 2009.
11/1/2007 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Wormald R, Evans J, Smeeth L, Henshaw K. Photodynamic therapy for neovascular age-related macular degeneration. Cochrane Database of Systematic Reviews. 2007;(4).

Last reviewed July 2010 by Eric L. Berman, MD

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