What Is Fluorescein Angiography?

What to Expect When Undergoing This Test

A fluorescein angiography (FA) is a medical procedure where fluorescent dye is injected into the bloodstream to highlight blood vessels in the back of the eye so they can be viewed and imaged. The FA test is helpful for making a diagnosis, determining a treatment plan, or for monitoring affected blood vessels.  

Purpose of Test

Your doctor will recommend a fluorescein angiography test of they feel the blood vessels in the back of your eye aren’t getting enough blood flow. They may also request this test if they suspect an eye disorder, like macular edema, macular degeneration, ocular melanoma, diabetic retinopathy, retinal detachment, or another type of vein blockage inside the eye.

The FA test helps your doctor to see how well blood is flowing into your retina­—the thin layer of tissue lining the back of the eye on the inside of the eyeball. The retina’s purpose is to receive light and send signals back to the brain so you can see.

With the help of fluorescein dye and a special camera, the fluorescein angiography test can be a valuable tool for locating circulation problems, swelling, leaks, or abnormalities in blood vessels.

Ophthalmologist assesses retinal health
 caracterdesign / E+ / Getty Images

Risks and Contraindications

The risk of a serious allergic reaction with fluorescein angiography is rare. But it is still possible to experience an allergic reaction to the fluorescein dye.

The most common reaction risks associated with the fluorescein dye are nausea, vomiting, or hives. Some people may also experience dry mouth, a metallic taste in the mouth, increased salivation (saliva overproduction), sneezing, or an increased heart rate.

In rare cases where a person experiences a serious allergic reaction, they may develop the following symptoms:

  • Swelling in the larynx (voice box)
  • Hives—swollen red bumps that appear suddenly on the skin
  • Fainting or near fainting
  • Swelling of the lips, tongue, eyes, or face.
  • Wheezing, chest tightness, coughing, or shortness of breath

If you know or suspect you may have an allergic reaction, talk to your doctor. They may be able to give you something in advance of the procedure to prevent hives or itching or suggest another procedure. Minor allergic reactions can be treated with antihistamines.

If you are pregnant or think you might be pregnant, it is a good idea to avoid a fluorescein angiography procedure. The risks of fluorescent dye to an unborn fetus are unknown.

Before the Test

Because your pupils will be dilated for up to 12 hours after the test, you will need someone to drive you to the procedure and, even more important, to drive you home afterward.

If you wear contacts, bring a lens case with you because you will need to remove those before the procedure starts.

You will want to check with your doctor if it is OK to take all of your daily medications on the day of the procedure. Be sure to tell the clinician about any prescriptions, over-the-counter drugs, and dietary or herbal supplements you take.

During the Test

A fluorescein angiography procedure is usually done at your ophthalmologist’s office. It takes about 30 minutes to complete.

The FA test will start with the ophthalmologist inserting standard dilation eye drops into both your eyes to make the pupils dilate. Dilating the pupils will enlarge them and keep them from getting smaller when light is shined onto the eyes.

Next, the ophthalmologist will inject yellow-colored fluorescein intravenously into a vein in the arm. The dye will take about 10-15 minutes to travel through the bloodstream and eventually reach the blood vessels of the eyes allowing them to “fluoresce” or shine brightly.

As the dye passes through the retina, your doctor will use a camera to take pictures of the inner eye to determine any problems and figure out necessary treatment options. 

After the Test

The effects of the dilating drops can continue for up to 12 hours after the procedure and include blurry vision and sensitivity to light. Make sure you have a pair of sunglasses to wear after the procedure and someone to drive you home. Do not drive until the effects of the drops have completely worn off.

The fluorescein dye may cause your urine color to be darker or orange, but there is nothing to be alarmed about. This should resolve in a day or two.

In addition urine color changes, the fluorescein dye can make skin appear a bit yellow because the dye has traveled through your veins. Your skin should be back to normal in a few hours. And if the skin near the IV needle site burns, this is a side effect of the dye and will go away quickly after the procedure.

Interpreting Results

Your doctor will contact you after they have an opportunity to review the images they have taken of the retina and blood vessels of the eye.

If your eyes are healthy, blood vessels will appear normal and not show any blockages or leaks. Abnormal results will show leakage or blockage.

Abnormal results may indicate any number of conditions from a blood flow problem, to high blood pressure, inflammation or edema, diabetic retinopathy, macular degeneration, or another eye disorder.

Your doctor is the best position to interpret fluorescein angiography test results and give you appropriate feedback and information about additional testing and necessary treatments.

A Word From Verywell

A fluorescein angiography test can be a valuable tool for diagnosing eye disorders, but it is not the only testing method your doctor will use. Other testing methods like ocular coherence tomography (OCT) can be just as valuable for studying the structure of the eyes.

Talk to your doctor about all the options that might be available to you for assessing eye problems. And don’t be afraid to ask questions and speak up if you don’t understand something or want additional testing or a second medical opinion. 

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Article Sources
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