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For people over 50, one of the most essential parts of the regular annual eye exam is testing for age-related macular degeneration (AMD). This common condition causes the patient to gradually lose their central vision, leaving them with a fuzzy, dim, grey, or even completely blacked-out region right in the center of their field of vision.

Vision lost to AMD cannot be recovered, but treatments and lifestyle changes can slow the progression of AMD and help patients maintain more of their vision for longer. That’s why an annual test for macular degeneration is so important—it allows eye care specialists to identify and begin treatment of AMD before the vision loss becomes severe.

This month, we’ll look at how eye care specialists test for macular degeneration.

What Is Macular Degeneration?

AMD takes two forms: dry AMD and wet AMD. Both affect a small part of the retina called the macula. The macula is densely packed with light receptor cells and is responsible for the ability to see fine details and provides the central portion of the field of vision.

Dry AMD is the most common form (about 80% of AMD cases) and is slower in progression than wet AMD. As we age, our macula grows thinner, and clumps of protein can begin to grow on the surface of the retina. This protein buildup, or drusen, and thinning of the macula cause the slow, gradual loss of central and fine vision.

Wet AMD is far less common but progresses much more rapidly. It is caused by the growth of new and abnormal blood vessels behind the retina. These vessels leak blood into the eye, damaging the light receptors in the macula.

How Eye Care Professionals Test for Macular Degeneration

Ophthalmologists and other eye specialists use a number of tests to detect AMD in its early stages.

Amsler Grid Test

The first test for macular degeneration will usually be an Amsler grid test. An Amsler grid is a specific type of eye chart that contains, as the name suggests, a grid of horizontal and vertical lines with a small black dot in the center.

Your eye doctor will cover one of your eyes and ask you to look at the dot in the center of the chart. You’ll tell them if any of the lines appear blurry or wavy, if there’s any distortion in the lines of the grid, or if there are any blank or dim spots. The procedure will then be repeated with the other eye.

Direct Observation of the Macula

The second test is usually a direct observation of the back of the eye. Your doctor will administer dilating eye drops to widen your pupil and use a special magnifying lens to look through your eye to see the retina and observe any physical changes that may indicate the onset of AMD.

Optical Coherence Tomography (OCT)

Optical coherence tomography relies on a special high-resolution scanner that uses light waves to take cross-sectional images of the eye. Following an OCT, an eye doctor can see each individual layer of the retina and identify any abnormalities.

An OCT is painless and non-invasive. Your eyes will be dilated, and you’ll be seated in front of a special machine. The machine features a support on which your head will rest to help you keep it motionless. Once you’re seated and properly positioned, the machine will spend 5-10 minutes making a detailed scan of the back of your eye.

If wet AMD is suspected, a related scan, optical coherence tomography angiography (OCTA), is used. OCTA uses the same technologies to create detailed images of the blood vessels on the back of your eye, allowing your doctor to spot abnormal or leaky blood vessels.

Fluorescein Angiography

Fluorescein angiography involves injecting a special yellow dye into the bloodstream and capturing detailed images of the blood vessels in the eye as the dye flows through it.

For a fluorescein angiogram, your doctor will inject fluorescein, a safe fluorescent yellow dye, into a vein in your arm. Then, they will use a special camera to take photos of the retina and observe the blood flow into and around the eye.

If any of these tests show that you may be suffering from AMD, your eye doctor will discuss treatment options and next steps.

Test for Macular Degeneration at Home

You can also test for macular degeneration at home. Dozens of websites offer free Amsler grid downloads that you can print out on your normal home printer. Place your Amsler grid in a convenient location that you see every day; many people put them on their bathroom mirror or refrigerator door.

Every day, you can perform a quick test for macular degeneration:

  • Stand or sit 12”-15” away from the grid
  • Cover one eye and look directly at the black dot in the center of the grid.
  • Note if any part of the grid seems blurry, dim, wavy, or otherwise distorted.
  • Repeat with the other eye.

If you begin to see distortion in the Amsler grid, contact your eye doctor and set up an appointment immediately. The faster you act to treat AMD, the more likely you are to preserve more of your central and fine vision.

Concerned About Macular Degeneration? We Can Help.

Don’t wait until your vision suffers. An annual eye exam is the best defense against macular degeneration. With eight locations around the midstate and the Golden Isles, we’re always close at hand to help you maintain clear vision! Call 478-923-5872 to learn more or make an appointment.

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Low Vision Part 2: Wet and Dry Macular Degeneration

Treatment for Are-Related Macular Degeneration