Fluorescein and indocyanine green angiography are diagnostic tests which use special cameras to photograph the structures in the back of the eye. In both tests, a colored dye is injected into a vein in the arm of the patient. Neither test involves the use of X-rays or harmful forms of radiation.
Fluorescein is a yellow dye which glows in visible light.
Indocyanine green angiography has only recently become a practical technique as these cameras have just become available. Schematic drawing illustrating a cross-section of the back of the eye with indocyanine green dye in the both the retinal blood vessels and the deeper choroidal vessels. Both tests can help retina specialists diagnose and evaluate specific eye diseases. Certain eye disorders, such as diabetic retinopathy and retinal vascular occlusive disease affect primarily the retinal circulation and are usually imaged with fluorescein dye. In other disorders, such as age-related macular degeneration, where leakage is from the deeper choroidal vessels, both tests may be useful.