Age-related macular degeneration: Is your sight at risk?

July 19, 2022 in Uncategorized  •  By Miles Varn, MD
macular degeneration

As the U.S. population ages, the number of people living with age-related macular degeneration (AMD), a leading cause of vision loss in people 55 and older, has grown substantially. Less than 10 years ago, CDC data noted that 1.8 million Americans had been diagnosed with this disease. Today, according to the National Eye Institute, 11 million Americans have been diagnosed with AMD. And the number of people affected is expected to continue to grow substantially. Some research projects that the number of people in the U.S. with AMD will reach 22 million by 2050.

What is age-related macular degeneration?

AMD is a disease that affects the retina (light-sensing nerve tissue at the back of your eye). The macula is the very small, central part of retinal tissue. It has the largest number of light-sensitive cells, which are necessary for the precise vision involved in activities like reading and close work.

There is a layer of blood vessels under the macula that nourish the tissue. The retinal pigment epithelium, another layer of tissue, moves nutrients from those blood vessels to the macula and removes the waste created by cells. As you get older, the retinal pigment epithelium can get thinner and less effective at delivering nutrients and removing waste. When waste builds up, the macula gets damaged, distorting and diminishing your central field of vision, but sparing your peripheral vision. AMD usually starts in one eye, then develops in the other eye over time.

There are two forms of the disease—dry AMD and wet AMD.

  • Dry AMD is the early and most common form of the disease. Waste products build up in the lower layers of the retina and create deposits called drusen. This buildup causes gradual loss of sight in the center of your field of vision.
  • Wet AMD is the more severe form of the disease. It involves overgrowth of blood vessels under the macula that leak fluid or blood, often causing sudden loss of central vision.

In its earliest stages, dry AMD doesn’t usually cause any symptoms. As the disease progresses to the intermediate stage, many people still have no symptoms or experience only mild symptoms like needing more light to read or mild blurriness in the center of your visual field.

In the later stages of both forms of AMD, symptoms include:

  • Straight lines look wavy or bent
  • Print blurs while reading
  • Colors appear duller
  • Trouble recognizing faces
  • A well-defined blurry or blind spot in the center of your vision

What increases the risk of AMD?

Some of the factors that increase your risk of developing AMD are things you cannot change, such your age, being female, light eye color, being Caucasian, and a family history of macular degeneration. There are also risk factors that you can control, including:

  • Not smoking
  • Maintaining a healthy weight and waist circumference
  • Managing heart disease and cholesterol levels
  • Eating a healthy diet that includes antioxidant-rich foods like leafy greens and food containing omega-3 fatty acids like salmon and walnuts
  • Avoiding high fat and sugar foods
  • Drinking fewer than 3 servings of alcohol a day

Treatment options and new treatments in development

Currently, there is no cure for macular degeneration. But there are treatments that can slow the progression of the disease and prevent AMD from progressing to its most severe form.

For people with intermediate or advanced dry AMD, the AREDS2 study found that a special high dose vitamin and mineral formula containing specific amounts of vitamins C and E and lutein, zeaxanthin, zinc oxide, and cupric (copper) oxide was associated with a reduction in the risk of vision loss.

There are several treatment options for the more severe, wet form of AMD, including:

  • Anti-vascular endothelial growth factors (anti-VEGF) medications that are injected into the eye to prevent the overgrowth of blood vessels. FDA-approved medications include bevacizumab (Avastin), ranibizumab (Lucentis), aflibercept (Eylea), and brolucizumab (Beovu). This is the most common treatment for AMD.

Less common treatments include:

  • Photocoagulation: Laser light seals and destroy abnormal blood vessels under the macula. Whether this approach is appropriate for you depends on the location of the blood vessels, how much fluid or blood has already leaked, and how healthy the macula is.
  • Photodynamic therapy: After an injection of a medication that is absorbed by the abnormal blood vessels under the macula, a cold laser is shined in the eye, activating the medication and sealing leaking blood vessels.

Researchers are exploring new approaches to treating AMD including gene therapy, new medications that target multiple causes of AMD, and immunotherapy treatments.

Macular degeneration can be detected during a simple exam with dilation of the pupils, so make an annual eye exam with an experienced ophthalmologist part of your preventive care routine. A health advisor can connect you with ophthalmologists experienced in treating patients at higher risk of AMD and provide evidence-based information about treatment options to help you make an informed decision.