Indocyanine Green Angiography
A photographic study of the back of the eye utilizing indocyanine green dye.
Alternative Names: ICG
What to Expect
Risks and benefits of the procedure will be discussed with the patient before the test is administered. You must sign an informed consent form. Tell the health care provider if you have a hypersensitive reaction to iodine.
- Dilating drops will be administered to dilate the pupils.
- The chin is placed in a chin rest and the forehead against a support bar to keep the head still during the test.
- Typically, a vein in the forearm (antecubital fossa) is located and the dye injected.
- After the dye is injected, the needle is removed and pressure applied to the injection site for several minutes.
- The dye is carried by the bloodstream throughout the whole body, reaching the eye in about 10 seconds.
- Photographs are taken at different intervals up to 30 minutes after the injection.
There is a slight chance of infection any time the skin is broken. Rarely, a person with sensitivity to the dye may experience:
- Increased heart rate
- Rarely, serious allergic reactions may occur
ICG dye should be used with caution in patients with a history of allergy to shellfish or iodides.
How the Test Feels
When the needle is inserted, a small amount of pain or stinging is usually felt. With the injection, mild nausea and a warm sensation may be experienced.
Why the Test is Performed
ICG dye permits visualization of blood vessels in the choroid and retina and may be helpful in establishing a diagnosis and/or guiding treatment.
- Normal Values
Normal values will show the vessels appearing of normal size without leakage or blockage.
- Abnormal Results
An abnormal value on ICG can detect:
- Macular degeneration
- Idiopathic polypoidal choroidal vasculopathy (IPCV)
- Other vascular conditions