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A close-up of an elderly's eyeball.

Protect Your Vision – Know the Difference Between Wet and Dry AMD

Wet vs Dry Macular Degeneration

Macular degeneration involves damage to the central part of the retina, which is called the macula. The macula is the part of the retina that allows us to see details, such as faces. We also need central vision to do most tasks, such as reading and driving. Once the macula becomes damaged or deteriorates, it affects your ability to receive and interpret images correctly. Eventually, it can lead to legal blindness.

In most cases, macular degeneration is related to aging. Age-related macular degeneration (AMD) is common. According to the American Academy of Ophthalmology (AAO), AMD is one of the primary causes of vision loss in adults over 50. But when it comes to wet vs dry macular degeneration, there is a clear difference.

Types of Macular Degeneration


There are two forms of macular degeneration. Both types are considered age-related since they primarily affect people over age 50. Both types involve damage to the macula. The two types of age-related macular degeneration are:

Dry

According to the American Macular Degeneration Foundation, dry AMD is much more common than wet AMD. Roughly 90% of people with macular degeneration have the dry form of the condition. With dry AMD, the layers of the macula become thinner, which makes them function less efficiently.

Small piles of fatty deposits called drusen also form under the retina. Drusen may be hard and spread out. They may also be soft, become large and cluster together. A few drusen are normal as we age. But when drusen become large and numerous, they can also cause deterioration of the retina and dry macular degeneration.

Wet

Wet macular degeneration also causes damage to the retina. It occurs when blood cells grow abnormally behind the retina. The abnormal cells are weak, and they leak blood and fluid into the tissue layers of the macula. This leads to scar tissue and damage to the macula. In some cases, dry AMD progresses into wet AMD.

Differences Between Wet and Dry Macular Degeneration

Since both wet and dry macular degeneration result in damage to the macula, they share some similarities. But there are also a few differences, especially in treatment.

Symptoms

Symptoms of wet and dry macular degeneration are similar:

  • Distorted vision, such as straight lines, may appear wavy
  • Trouble recognizing faces
  • Blurriness of print
  • Decreased vividness of colors
  • Decreased central vision
  • Trouble seeing in low light

The biggest difference in symptoms is onset. People with dry macular degeneration may have gradual symptoms that occur over a few years. But symptoms of wet macular degeneration may appear more abruptly and worsen quickly.

Causes

What makes some people develop either form of AMD is not fully known. Researchers think it is a combination of environmental factors and heredity risks.

Certain risk factors have been identified for both forms of AMD. According to the Mayo Clinic, most people who develop either type of AMD are over the age of 50.

Additional risk factors:

  • Smoking
  • Obesity
  • Having a family history of AMD
  • Race (Caucasians have a higher risk than Hispanics and African Americans)

Diagnosis

Both types of AMD are diagnosed the same way. During an eye exam, your doctor will use a special lens to look into the eyes and view changes to the retina. One sign of AMD the doctor looks for is drusen.

In addition to an eye exam, your eye doctor may perform a fluorescein angiography. During the procedure, the doctor injects dye into a vein in the arm, which travels to the vessels in the eyes. This procedure allows the doctor to use a camera to check for new abnormal blood vessels in the eyes. This diagnostic test helps determine if macular degeneration is wet or dry.

Although symptoms may develop suddenly with wet AMD, dry AMD may not have noticeable symptoms at first. But a comprehensive eye exam can diagnose the condition. An early diagnosis may help slow the progression of the disease.

Treatments

Treatment for macular degeneration depends on the form of the disease a person has.

Wet AMD Treatment

People with wet AMD are believed to produce too much of a protein called vascular endothelial growth factor (VEGF). This protein may cause abnormal blood vessel growth. Treatment for wet AMD includes anti-VEGF medication that inhibits the growth of abnormal vessels in the retina.

The medications are injected into the eye. Currently, the medications for wet AMD are:

  • Avastin
  • Lucentis
  • Eylea

Dry AMD Treatment

Currently, there is no treatment for dry AMD. But people with early AMD are often prescribed a combination of vitamins to slow the progression of the disease.

Research continues on the role of vitamins in reducing vision loss in people with dry AMD, but according to the AAO, the following combination of vitamins and minerals, called the AREDS2, may help:

  • Copper (2 milligrams)
  • Vitamin C (500 milligrams)
  • Vitamin E (400 IU)
  • Lutein (10 milligrams)
  • Zeaxanthin (2 milligrams)
  • Zinc (80 milligrams)

Rehab for Macular Degeneration

Regardless of which form of macular degeneration a person has, if vision loss progresses, low vision rehabilitation may help. Rehab does not reverse vision loss or prevent further loss. Instead, it helps people adapt to low vision and learn ways to maintain their independence.