Angiography



A technique called angiography is the most useful test for determining the presence of choroidal neovascularization (CNV). The procedure is not painful and very safe. The patient will be seated at a fundus camera, which takes pictures of the retina. A small IV catheter is inserted into a large vein, usually in the arm. Several pictures are taken at this time.
Fundus camera The fundus camera takes pictures of the fundus, or retina. The camera may use film, or it may display the images on a computer screen.
		A small IV catheter is inserted into a vein for the injection of fluorescein or ICG dye.
Then, a dye is injected into the vein. The dye circulates throughout the blood vessels of the body. As the dye enters the blood vessels of the eye, a series of photographs is taken of the retina. Special filters make the dye stand out against the background of the retina. By looking at the pattern of the blood vessels and observing whether dye leaks from any of the vessels as time passes, your ophthalmologist can locate sites of choroidal neovascularization if they are present.
This fluorescein angiogram shows choroidal neovascularization (CNV) in the macula. The bright area indicates dye leaking from the neovascular vessels. Click here to watch an 850 KB movie that explains the procedures used in angiography. You will need a QuickTime Plugin:
Two dyes are commonly used in ophthalmology: an orange dye called fluorescein and a green dye called indocyanine green. These dyes are different than those used for angiograms of the heart or brain. Unlike angiography used in other parts of the body, X-rays are not used in this procedure since the examiner can look through the pupil and see the blood vessels directly. The majority of treatable CNV can be seen with fluorescein dye. Fluorescein angiography is an extremely safe procedure, and it has been performed in millions of patients for over twenty years. The overwhelming majority of patients experience no symptoms when the dye is injected. A small minority may feel flushed or briefly nauseated. Rarely, someone has an allergy to fluorescein and may experience itching or other symptoms that require treatment.
	This ICG angiogram shows a bright area of CNV in the macula (red arrow). The CNV was not visible with fluorescein dye because of abnormal fluid beneath the retina.