What Is Fluorescein Angiography?

What to Expect When Undergoing This Test

Fluorescein angiography (FA) is a medical procedure in which 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. This is a safe procedure, but there are some risks, including an allergic reaction.

Purpose of Test

Your healthcare provider will recommend FA if there is a concern about blood flow in the blood vessels in the back of your eye. This test may be indicated for the evaluation of macular edema, macular degeneration, ocular melanoma, diabetic retinopathy, or another type of vascular disease inside the eye.

An FA procedure can help your healthcare provider assess blood flow in 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, FA can be a valuable tool for identifying circulation problems, swelling, leaks, or abnormalities of the blood vessels.

Ophthalmologist assesses retinal health
 caracterdesign / E+ / Getty Images

Risks and Contraindications

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

The most common reactions 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.

An allergic reaction can produce 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 have a history of allergic reactions, talk to your healthcare provider. They may be able to give you a pre-treatment before your procedure to prevent hives or itching or might suggest another procedure. 

And if you experience any allergy symptoms during or after your procedure, tell your healthcare provider right away. Minor allergic reactions can usually be treated with antihistamines, but more severe reactions may necessitate an urgent intervention.

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

Before the Test

You should check with your healthcare provider to see 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.

Your pupils will be dilated for up to 12 hours after the test, so you will need someone to drive you home after your procedure.

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

During the Test

FA is usually done at your ophthalmologist’s office. It takes about 30 minutes to complete.

Your ophthalmologist will start by placing standard dilation eye drops into both of your eyes to make your pupils enlarge and keep them from getting smaller when light is shined onto the eyes.

Next, your ophthalmologist or an assistant will inject yellow-colored fluorescein intravenously into a vein in your 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 healthcare provider will use a camera to take pictures of your inner eye.

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 be sure you have someone to drive you home. Do not drive until the effects of the drops have completely worn off.

  • You can have a burning sensation on the skin near the IV needle site. This is a side effect of the dye and will go away quickly after the procedure.
  • The fluorescein dye can also make your skin appear a bit yellow. Your skin color should be back to normal in a few hours.
  • The fluorescein dye may cause your urine to appear dark or orange, but this is nothing to be alarmed about. This should resolve in a day or two.

Interpreting Results

Your healthcare provider will contact you to discuss your results and next steps after reviewing the images of your retina and blood vessels.

The blood vessels in your eyes may appear normal and might not show any blockages or leaks.

Abnormal results may signal issues like high blood pressure, inflammation, edema, diabetic retinopathy, macular degeneration, or another eye disorder. Leakage or blockage of blood vessels is considered abnormal.

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 healthcare provider 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 healthcare provider about the options that might be available to you for assessing your eye problems. And don’t be afraid to ask questions if you don’t understand something or if you want to seek a second medical opinion. 

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Porter D. What is fluorescein angiography? American Academy of Ophthalmology.

  2. American Academy of Ophthalmology. Retina

  3. Spaide RF, Klancnik JM Jr, Cooney MJ. Retinal vascular layers imaged by fluorescein angiography and optical coherence tomography angiography. JAMA Ophthalmol. 2015 Jan;133(1):45-50. doi: 10.1001/jamaophthalmol.2014.3616

  4. American Academy of Allergy, Asthma & Immunology. Medications and drug allergic reactions.

  5. American Academy of Ophthalmology. Diagnostic agents.

  6. Boyd K. American Academy of Ophthalmology. What Are Dilating Eye Drops?

  7. MedlinePlus. Fluorescein angiography.

By Lana Barhum
Lana Barhum has been a freelance medical writer since 2009. She shares advice on living well with chronic disease.