Indocyanine green dye fluorescence and infrared absorption choroidal angiography performed simultaneously with fluorescein angiography

Abstract

The sensory retina of the eye is nourished by two essentially separate blood circulations. The more superficial of these, the retinal circulation, is easily evaluated by direct visualization or routine fluorescein angiography. However, the underlying choroidal circulation, which is attributed with maintenance of the outer layers of the retina is not easily visualized due to the pigment epithelial layer and choroidal pigment. Fluorescence and infrared absorption angiographic techniques using indocyanine green (ICG) dye, which can be used to evaluate the choroidal circulation routinely, are described in this paper. A method is also described which can provide these angiograms simultaneously with standard fluorescein fluorescence angiograms of the retina. Finally, a comparison of all three types of angiograms is made. Limitations to the resolution of fundus details in angiograms imposed by optics of the fundus camera, photographic films, and optics and anatomy of the eye are examined.