What Is a Fluorescein Angiography?
A fluorescein angiography is a medical procedure in which a fluorescent dye is injected into the bloodstream. The dye highlights the blood vessels in the back of the eye so they can be photographed.
This test is often used to manage eye disorders. Your doctor may order it to confirm a diagnosis, to determine an appropriate treatment, or to monitor the condition of the vessels in the back of your eye.
What the Test Addresses
Your doctor may recommend a fluorescein angiography to assess if the blood vessels in the back of your eye are receiving adequate blood flow. It can also be used to diagnose eye disorders.
According to the National Institutes of Health (NIH), this age-related disorder is the number one cause of vision loss in people 60 and older in the United States (NIH).
Macular degeneration strikes the macula, the part of the eye that lets you focus on fine detail. Sometimes the disorder worsens so slowly that you may not notice any change at all. However, in some cases, your vision deteriorates rapidly and may lead to blindness in both eyes.
Because the disease destroys your focused, central vision, it prevents you from seeing objects clearly, driving, reading, and watching television.
This eye disorder is caused by long-term diabetes and results in permanent damage to the blood vessels in the back of the eye (or the retina). The retina converts images and light that enter the eye into signals, which are then transmitted to the brain via the optic nerve.
There are two types of this disorder:
- non-proliferative diabetic retinopathy: this is the initial stages of the disease
- proliferative diabetic retinopathy: this condition develops later and is more severe
The National Library of Medicine states that most people who suffer from diabetes for more than 30 years also develop diabetic retinopathy (NLM, 2012).
Your doctor may order fluorescein angiography to determine if treatments for these eye disorders are working.
Preparation for the Test
You will need to arrange for someone to pick you up and drive you home since your pupils will be dilated for up to 12 hours after the test.
Be sure to tell your doctor before the test about any prescriptions, over-the-counter drugs, and herbal supplements you are taking. You should also tell your doctor if you have an allergy to iodine.
If you wear contact lenses, they must be taken out before the test.
How Is the Test Administered?
Your doctor will perform the test by inserting standard dilation eye drops into your eyes. These make your pupils dilate. He or she will then ask you to rest your chin and forehead against the camera’s supports so that your head remains still throughout the test.
Your doctor will then use the camera to take a number of pictures of your inner eye. Once your doctor has completed the first batch of pictures, he or she will give you a small injection in a vein in your arm. This injection contains a dye called fluorescein. Your doctor will then continue to take pictures as the fluorescein moves through the blood vessels into your retina.
Understanding the Results
If your eye is healthy, the blood vessels will have normal shape and size. There will be no blockages or leaks in the vessels.
Abnormal results will reveal a leak or blockage in the blood vessels. This may be due to:
- circulatory problems
- diabetic retinopathy
- macular degeneration
- elevated blood pressure
- enlarged capillaries in the retina
- swelling of the optic disc
What to Expect After the Test
Your pupils can remain dilated for up to 12 hours after the test is performed. In addition, the fluorescein dye may cause your urine to be darker and orange in color for a few days.
If your doctor diagnoses you with diabetic retinopathy or macular degeneration, he or she may prescribe medications to help manage the disorders.
What Are the Risks of the Test?
Mild to severe reactions occur in five to 10 percent of all patients (MDS, 2002). Possible reactions include nausea and vomiting.
More rarely, severe reactions may occur, such as:
- swelling of the larynx
- difficulty breathing
- cardiac arrest
If you are pregnant or think you may be, you should avoid having a fluorescein angiography. The risks to an unborn fetus are not yet known.