An Overview of Macular Degeneration

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Macular degeneration, often referred to as age-related macular degeneration (ARMD or AMD), is the leading cause of blindness in the United States. The condition primarily affects people age 65 and older. Some macular complications that affect younger people may be referred to as macular degeneration, but the term generally refers to age-related macular degeneration. AMD affects the macula, the sensitive part of the retina responsible for sharp, central vision. AMD can be treated, though not cured.

  • Dry (Non-Neovascular) AMD
    • Dry AMD, also called non-exudative macular degeneration, is the most common type, accounting for about 90 percent of all AMD cases. In dry AMD, an observable change in the pigmented cells of the eye occurs, leaving areas of depigmentation, pigment clumping, and drusen (yellow deposits under the retina).
    • Dry AMD usually progresses very slowly. There are three stages: early, intermediate, and advanced. The earliest stage is characterized by drusen and normal vision or mild visual loss. Central vision loss widens, additional drusen may appear or enlarge, and pigmentary changes develop as the condition advances. The degree of vision loss varies with dry AMD but rarely progresses to legal blindness. Macular tissue atrophy and mild scarring may develop.
  • Wet (Neovascular) AMD
    • Wet AMD accounts for approximately 10 percent of all AMD cases. People with the dry form of AMD may progress to the more severe wet form. New blood vessel growth (neovascularization) occurs underneath the retina. Although these vessels are new, they are frail in nature. Blood and fluid leak out of the new blood vessels, often lifting the macula and causing visual distortions, potentially resulting in permanent tissue damage. Scarring may occur, causing significant loss of vision and, many times, legal blindness.

Other macular degeneration diagnoses include:

  • Geographic Macular Degeneration
    • Geographic macular degeneration is an advanced form of dry macular degeneration. Here, there is a general, larger area of loss of the retinal pigment epithelial cells (RPE). The RPE, which gives the back of the eye a characteristic red-orange color, helps to nourish the photoreceptors of the eye, the rods and cones. As a result, anything that causes disease in the RPE will eventually affect the rods and cones in the retina.
    • It is called "geographic" because the large areas of lost RPE appear like continents surrounded by a sea of a healthy retina. Sometimes it is described as RPE dropout. Typically, there is no fluid leakage or bleeding, and the loss of vision occurs very slowly. Doctors are studying gene therapy and RPE transplantation treatment.
  • Juvenile Macular Degeneration
    • Juvenile macular dystrophy or degeneration is inherited and affects young people and children. Usually, the condition is autosomal recessive, meaning that it develops when a child receives a recessive gene from each parent. Juvenile macular degeneration does not affect side vision or peripheral vision. People who develop juvenile macular degeneration lose central vision and do not become blind. There are two main forms of juvenile macular degeneration: Stargardt's disease and Vitelliform macular dystrophy.

    Symptoms

    Vision loss in macular degeneration is so gradual that you might not notice it at the beginning. There is usually no pain. As the disease progresses, your vision may be blurred and objects may appear distorted. Some people with AMD may complain of missing letters in words or difficulty seeing smaller print.

    As the condition advances, there may also be a profound loss or graying of central vision, while peripheral vision remains unchanged. Sometimes, color vision may be altered.

    Signs of AMD will also be present, though they're best detected by an eye health professional.

    Causes

    The most common types of macular degeneration related to advancing age. There are also several other known risk factors for developing age-related macular degeneration:

    • Age
    • Smoking
    • Family history
    • Light eye color
    • Hypertension
    • Sun exposure
    • Cardiovascular disease
    • High cholesterol
    • Obesity
    • Female gender
    • Farsightedness

    Your environment may also contribute to the development of AMD, and current research is focusing on genes that may increase or decrease the risk of developing AMD.

    Diagnosis

    The diagnosis of AMD is made after a comprehensive eye examination is performed by an optometrist or ophthalmologist. 

    Distance and near vision are also measured. A test called an "Amsler grid" is performed to locate blind spots, waving lines, or distortions in vision. A dilated retinal exam allows the doctor to see a magnified view of the macula.

    Your eye doctor will look for signs such as:

    • Drusen and changes to the pigmented cells in the macula, due to cellular debris build-up 
    • New blood vessel growth (neovascularization): A perceived lack of oxygen in the retina may signal chemical mediators that cause this.
    • Fluid or blood that has leaked into retinal tissue (due to new blood vessels, which are weak as they are forming)

    If AMD is suspected, a dye-injection test, fluorescein angiography (FA), may be ordered. Another diagnostic test, optical coherence tomography (OCT), may also be performed. If AMD is detected, a referral to a retinal specialist comes next.

    Treatment

    There is no known cure for macular degeneration. AMD treatment focuses on delaying or lessening the progression of the disease and varies depending on its stage.

    Based on the Age-Related Eye Disease Study (AREDS), nutritional supplements containing vitamins C and E, beta-carotene, and zinc were shown to slow or delay the progression of dry AMD to advanced AMD by 28 percent in some people with the condition.

    Treatment for wet AMD focuses on stopping the fluid leakage from neovascularization. Procedures such as photocoagulation and macular translocation have been performed with variable results. Anti-vascular endothelial growth factor (anti-VEGF) medications are being used for the treatment of macular degeneration. These medications are injected directly into the eye and act to stop new blood vessels from forming.

    If you have significant vision loss due to AMD, low vision centers and doctors can recommend products or home modifications that can give back functional vision and improve your quality of life. Some of these devices include high-powered reading glasses or bifocals, telescopic lenses, hand-held devices, magnifiers, and closed-circuit televisions. Other recommendations, such as using large numbered clocks and stove dials, large print books, writing templates and electronic talking devices, may dramatically improve your quality of life with macular degeneration.

    Coping

    Living with the vision loss of macular degeneration may require making lifestyle adaptations. Important aspects of life that are impacted include driving, reading, and conducting fine motor tasks that require a full range of vision, such as sewing and using tools. In some cases, activities may need to be suspected. But in others, assistive devices (like magnifiers) and modifications may help and allow you to continue on.

    Social support is helpful, not just to help you adjust but to also assist you with day-to-day tasks if needed. You may also consider exploring offerings like public transportation.

    A Word From Verywell

    It is important to get regular eye examinations as part of your routine health maintenance throughout your life, even if you do not have vision loss. If evaluations show that you have early signs of macular degeneration, be sure to follow up with your eye doctor as recommended and adhere to the suggested steps to halt the condition from advancing, as this can make a difference in preventing vision loss.

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