Fluorescein angiography

Definition

Fluorescein angiography is an eye test that uses an orange-colored, fluorescent dye (fluorescein), and a special camera, to take pictures and analyze the blood circulation in the retina and choroid.

How the test is performed

Mydriatic eye drops (drops that make the pupil dilate) are administered. The chin is placed on a chin rest, and the forehead against a support bar to keep the head still during the test.

Photographs of the inside of the eye are taken. Then, dye is injected into a vein, usually at the bend of the elbow (the antecubital vein).

As the dye is injected, a series of photographs are taken. Afterwards, the needle is removed and pressure is applied to the injection site for several minutes.

More photographs are taken up to 20 minutes after the injection.

Allergy to the dye is rare, but may occur. A history of allergies will be taken before the test.

How to prepare for the test

Arrange for transportation because your vision may be blurred up to 12 hours after the test. The health care provider may instruct you to discontinue drugs that could affect the test. You must sign an informed consent form. You must remove contact lenses before the test. Tell the health care provider if you have a hypersensitive reaction to iodine. Tell the health care provider if you may be pregnant.

How the test will feel

When the needle is inserted, a small amount of pain or stinging may be felt. When the dye is injected, mild nausea and a warm sensation may be experienced. These symptoms are usually very brief.

Why the test is performed

This test is useful in determining if there is proper circulation in the retinal vessels. It can also be performed to diagnose or follow treatment of problems in the eye.

Normal Values

Normal values will show the vessels appearing of a normal size and without blockages or leakage. If blockage or leakage is present, the pictures will map the location for possible treatment.

What abnormal results mean

An abnormal value on a fluorescein angiography can detect:

• Diabetic or other retinopathy
• Macular degeneration
• Cancer
• Tumors
• Circulatory problems
• Inflammation or edema
• Microaneurysms -- enlargement of capillaries in the retina. Microaneurysms are the earliest signs of Diabetic retinopathy
• Papilledema (swelling of the optic disc)

• Diabetic retinopathy
• Hypertensive retinopathy
• Macular degeneration
• Retinal detachment
• Retinal vessel occlusion
• Retinitis pigmentosa

What the risks are

There is a slight chance of infection any time the skin is broken. Rarely, a person is hypersensitive to the dye and may experience:

• Nausea and vomiting
• Dry mouth or increased salivation
• A "metallic" taste
• Feeling dizzy or faint
• Hives
• Sneezing
• Increased heart rate
• Rarely, serious allergic reactions may occur

Your urine will be darker for a day or two after the test.

Special considerations

Miotic eye drops (drops which cause contraction of the pupil) can prevent a clear view of the fundus by preventing wide dilation of the pupils.

People with cataracts will have less accurate test results because of the difficulty seeing the fundus.

References

Yanoff M, Duker JS, Augsburger JJ, et al. eds. Ophthalmology. 2nd ed. St. Louis, Mo: Mosby; 2004:800-805.

Singh AD, Rundle PA, Rennie I. Retinal vascular tumors. Ophthalmol Clin North Am. 2005 Mar;18(1):167-76, x.

Illustrations

Retinal dye injection

Page Content:

Retinal photography; Eye angiography ; retinal photography