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Adult Macular Degeneration

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Adult Macular Degeneration

(AMD)

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
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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.
  • 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 is very uncommon. But, it accounts for the majority of blindness from this disease.

Causes

The cause of AMD is not known.

Risk Factors

Factors that may increase your risk for AMD include:
  • Age: risk increases with age, and is most commonly seen in senior citizens
  • Family members with AMD
  • Race: White
  • Smoking
  • Excessive exposure to sunlight
  • Sex: women might have 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. Neither dry AMD nor wet AMD causes 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 your field of vision
  • Straight lines (such as 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 suggested 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 at the new blood vessels. The beam destroys the vessels. It usually takes less than 30 minutes to complete. You may need more 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 your 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 growing quickly 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 exams should include dilation to closely look at the retina.
  • If you smoke, quit.
  • Eat a healthy diet that is rich in fruits and vegetables.
  • Consider omega-3 fatty acid supplements.
If you have AMD, your doctor may advise you to use an Amsler grid at home. This will help you monitor for problems. 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 Alliance International 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, 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. Available at: http://dynamed.ebscohost.com/about/about-us: Wormald R, Evans J, et al. Photodynamic therapy for neovascular age-related macular degeneration. Cochrane Database of Systematic Reviews. 2007;(4).

3/6/2013 DynaMed's Systematic Literature Surveillance. Available at: http://dynamed.ebscohost.com/about/about-us: Sui GY, Liu GC, Liu GY, et al. Is sunlight exposure a risk factor for age-related macular degeneration: A systematic review and meta-analysis. Br J Ophthalmol. 2012 Nov 10. [Epub ahead of print].

3/11/2013 DynaMed's Systematic Literature Surveillance. Available at: http://dynamed.ebscohost.com/about/about-us: Christen WG, Glynn RJ, Sesso HD, et al. Vitamins E and C and medical record-confirmed age-related macular degeneration in a randomized trial of male physicians. Ophthalmology. 2012 Aug;119(8):1642-9.

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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