Fluorescein Angiography

What is Fluorescein Angiography?

Fluorescein angiography is a diagnostic procedure which uses a special camera to take a series of photographs of the retina, the light sensitive tissue in the back of the eye
A special water-soluble dye (fluorescein) is injected into a vein in the arm. The dye travels through the veins and into the arteries which circulate throughout the the body. (This procedure is often confused with an x-ray angiogram where an iodine is injected into a vessel. This is not iodine). (1)
As the dye passes through the blood vessels of the retina, a special camera flashes a blue light into the eye and takes multiple photographs of the retina.
If the blood vessels are abnormal, the dye may leak into the retina or stain the blood vessels. Damage to the lining underneath the retina or the appearance of abnormal new blood vessels growing beneath the retina may also be revealed. The precise location of these abnormalities can be determined by a careful interpretation of the fluorescein angiogram by your ophthalmologist.

Why is Fluorescein angiography done?

If after examining your eyes, your ophthalmologist suspects abnormalities in the back of the eye, he or she may recommend fluorescein angiography. It is often done to follow the course of disease and monitor treatment results.
Diabetes, the leading cause of blindness in patients under the age of 55, can cause the blood vessels of the retina to leak fluid or blood. In some cases, theses abnormalities can be treated with a laser to help prevent loss of vision.
Age-related macular degeneration is the leading cause of blindness in patients over the age of 55. In some cases, small blood vessels can be seen under the retina which can be treated with a laser in attempt to prevent severe visual loss.
Without the help of fluorescein angiography, your ophthalmologist would not be able to throughly diagnose these and other abnormalities. Knowing exactly where a leak is, for example, can guide laser treatment with pinpoint accuracy.

What are the risks of fluorescein angiography?

After the fluorescein dye is injected, your skin may turn yellowish for several hours. This color disappears as the dye is filtered out of the body by the kidneys. Because the dye is removed by the kidneys, your urine will turn dark orange for up to 24 hours following the test.
Some individuals may experience slight nausea during the procedure, but this usually passes within a few seconds. If the dye leaks out of a fragile vein during the injection, some localized burning and yellow staining of the skin may occur. This burning usually last only a few minutes and the staining will go away in a few days.
Allergic reactions to fluorescein dye are rare. If they occur, they may cause a skin rash and itching. This is usually treated with oral or injectable antihistamines, depending on the severity of the symptoms. Even more rarely, severe allergic reactions (anaphylaxis) can occur and be life threatening. If this occurs, emergency treatment will be given.

What to expect on the day of your fluorescein angiogram?

This test involves taking a number of photographs of the inside of your eyes. these are not x-rays.
Before the photograph are taken you will be given eye drops to enlarge the pupils of your eyes. These drops sting slightly. If you wear contact lenses, we would like you to remove them for this procedure. Please bring your lens case.
As part of your test, a nurse will be giving you a small injection of yellow dye into a vein in your arm or hand. This is to color your blood so it will show on the photographs. During the test you must sit very still and keep your eyes open as widely as your can.
You should allow 1-2 hours for this test. If you are seeing your doctor or having treatment following the test your should allow 4 hours for your appointment.
Your vision may be blurred for up to 12 hours.
You should not drive until the effects of the dilating eye drops wear off. Arrange for someone to drive you home.
You should wear sunglasses until your pupils return to normal size Bright light and sunshine may hurt your eyes.

Sources: Vancouver Island Health Authority