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Pronunciations angiography corticosteroid endophthalmitis macula macular degeneration retina retinopathy

Age-related macular degeneration (also called age-related maculopathy) causes progressive damage to the macula, the central and most vital area of the retina, resulting in gradual loss of central vision.

• Central vision becomes washed out and loses detail, and straight lines may appear wavy.
• Changes in the eye that characterize the disorder can usually be seen by a doctor using a hand-held ophthalmoscope.
• Dietary supplements may help slow progression of the disorder.
• Eye injections and laser treatments may be necessary for some people.

Age-related macular degeneration is the most common cause of irreversible loss of central vision in the elderly. It is equally common in men and women.

Causes

The following are risk factors for the disorder:

• Older age
• Smoking
• Fair skin
• Certain genetic abnormalities
• High blood pressure
• A diet low in omega-3 fatty acids (for example, in certain fish) and dark green leafy vegetables

Types: There are two forms of age-related macular degeneration:

• Dry (atrophic)
• Wet (neovascular or exudative) macular degeneration

Ninety percent of people with macular degeneration have the dry type. However, 90% of the blindness caused by macular degeneration occurs in the 10% of people who have the wet form.

In dry macular degeneration, the tissues of the macula thin as cells disappear. Both eyes may be affected simultaneously in the dry form. There is no evidence of scarring or of bleeding or other fluid leakage in the macula.

Wet macular degeneration starts off as the dry type. In wet macular degeneration, abnormal blood vessels develop under the macula. These vessels may leak fluid and blood under the retina (hence the description as “wet”). Eventually, a mound of scar tissue develops under the retina. The wet form develops in one eye first but eventually may affect both eyes.

Symptoms

In dry macular degeneration, central vision slowly and painlessly worsens. Objects may appear washed out, or fine detail may be lost.

In wet macular degeneration, loss of vision tends to progress quickly and may be sudden if one of the abnormal blood vessels bleeds. The first symptom may be distortion of vision in one eye, so that fine, straight lines appear wavy. Often, difficulty with reading or watching television results.

Age-related macular degeneration can severely damage vision, but it usually does not lead to complete blindness. Vision at the outer edges of the visual field (peripheral vision) is generally not affected. The dry type tends to cause slower vision loss.

Diagnosis

Doctors can usually diagnose macular degeneration by examining the eyes with an ophthalmoscope or a slit lamp. The retinal damage is almost always visible even before symptoms develop. Sometimes fluorescein angiography—a procedure in which a doctor injects dye into a vein and photographs the retina—is used to confirm the diagnosis. Optical coherence tomography, an imaging study, can sometimes help in making the diagnosis.

Treatment

No treatment is currently available to undo damage from the dry type. No treatment is currently recommended for mild disease.

Dietary Supplements: People with moderate to severe dry macular degeneration and those who have wet macular degeneration in one eye benefit from high doses of antioxidants (vitamin C, vitamin E, and beta-carotene [a form of vitamin A Some Trade Names
AQUASOL A
]) and zinc, with a small amount of copper. People who have used tobacco products within the past seven years should not take beta-carotene or vitamin A Some Trade Names
AQUASOL A
because these supplements can increase the risk of developing lung cancer. Controlling high blood pressure and eating more omega-3 fatty acids and dark green leafy vegetables may help slow progression of the disorder.

Drug Treatments and Laser Procedures: In the wet type of macular degeneration, drugs such as ranibizumab Some Trade Names
LUCENTIS
, bevacizumab Some Trade Names
AVASTIN
, or pegaptanib Some Trade Names
MACUGEN
, can be injected into the eye to cause the new blood vessels to stop leaking. These injections need to be repeated every 1 to 2 months, but the injections can improve vision in some people and one in three people regains reading vision. Another treatment is photodynamic therapy. In this treatment, a substance that sensitizes the retinal blood vessels to laser light is injected into a vein in the arm, and then a beam of laser light is used to destroy the abnormal new blood vessels. If the new blood vessels are not directly under the macula, a thermal laser can be used to destroy them before they do further harm. Corticosteroid drugs can sometimes be injected into the eye. Surgery is used only if these other treatments are not working.

Adjusting to Vision Loss: Magnifiers, reading glasses, telescopes, and closed-circuit television magnifying devices may help people with poor vision. Computer users can select from a variety of low-vision aids. For example, one device projects an enhanced image from the computer onto an undamaged part of the retina. Certain types of software display computer data in large print or read the data aloud in a synthetic voice. Counseling regarding the types of services that are available for people with poor vision is advisable and is typically given by a low-vision specialist (an ophthalmologist or optometrist who specializes in treating people with very poor vision).

Last full review/revision November 2008 by Sunir J. Garg, MD