How Doctors Diagnose Wet Age-Related Macular Degeneration (Wet AMD)

If you’re having vision problems or have been diagnosed with dry age-related macular degeneration (AMD), your doctor may recommend testing to see if you have the wet form of AMD.

Your macula is part of the retina at the back of your eye. It allows you to see things directly in front of you -- which is your central or “straight ahead” vision -- as well as color and fine details.

With wet AMD, abnormal blood vessels grow under the macula and leak blood and fluid. That leaking can damage the macula and cause vision problems. That’s why your doctor may recommend you get tested for wet AMD if you have noticed that your vision is hazy or objects look skewed or curved (for example, if a straight line looks wavy to you).     

Though these vision problems are signs of wet AMD, they can also be signs of other eye conditions. So you’ll need to see your eye doctor to know if you have it.

How Is Wet AMD Diagnosed?

First, your eye doctor (an ophthalmologist) will talk to you about your health history, including any vision problems you have, and ask you about your family’s health history. Then your doctor will do a complete eye exam, which may include:

  • A visual acuity test, which uses an eye chart to check how clearly you see at different distances.
  • A refraction assessment. You’ll look through a series of lenses to determine what type of glasses, contact lenses, or surgery might improve your vision. 
  • Glaucoma screening, which measures the fluid pressure inside your eye.

Your eye doctor will also do other tests used to diagnose wet and dry AMD. These include: 

A retina exam, which lets your doctor check the retina at the back of your eye. You’ll get eye drops to wide (dilate) your pupils. Your eye doctor will then use a special magnifying lens to look at your optic nerve and retina to see if there’s blood, fluid, and evidence of drusen. (Drusen are yellow spots that often form under the retina.) These are all signs of AMD.

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A visual field test to check for problems in the center of your vision. Your eye doctor will use an Amsler grid, which is checkered and may have a dot located on it. For example, if you have wet AMD, you may see curved, distorted, or missing lines or blocks when you look at the center of the Amsler grid. If you have problems with your central vision, which is a sign of wet AMD, lines may also disappear or look wavy. 

A fluorescein angiogram. With this test, your eye doctor injects fluorescent dye into your arm, which shows leaking blood vessels in your eyes or other changes to your retina that may be a sign of advanced AMD. Since this test can sometimes cause complications, like nausea or an allergic reaction, your doctor may not do it during your regular eye exam. Instead, you may need to schedule a separate appointment. 

Optical coherence tomography (OCT). This is an imaging test. It lets your eye doctor see detailed cross sections of your retina. Your eye doctor will check for thinning, thickening, swelling in the retina, pigment changes, and drusen -- all of which can be signs of AMD. Your eye doctor can also use OCT to help decide if your retina will respond to treatment for AMD. OCT uses light waves to create high-resolution images of your tissues. Your eye doctor will dilate your eyes, then place your head on a chin rest while a machine beams a light into your eye to capture images of your retina. OCT isn’t painful.

Indocyanine green angiography. This test is rarely used. It involves injecting dye into your vein. It’s often used to spot abnormal blood vessels that are deep in your retina and to confirm the results of fluorescein angiogram.

Usually, testing for wet AMD and other eye problems involves one or more appointments that may each take several hours. In many cases, your doctor will be able to make a diagnosis soon after testing. Ask your eye doctor about what to expect and whether you’ll need someone to drive you home from your appointment or how long you’ll need to rest your eyes after dilation.

WebMD Medical Reference Reviewed by Alan Kozarsky, MD on August 24, 2019

Sources

SOURCES:

National Eye Institute: “Facts About Age-Related Macular Degeneration,” “What the Age-Related Eye Disease Studies Mean for You.”

Andrea Thau, OD, associate clinical professor emerita, SUNY State College of Optometry; past president, American Optometric Association.

Mayo Clinic: “Wet Macular Degeneration.”

American Academy of Ophthalmology: “Wet AMD Look-alikes.”

Genetic and Rare Diseases Information Center: “Adult-onset vitelliform macular dystrophy.”

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