This is a type of angiography used by a retina specialist to look for problems in the retina. With this test, indocyanine green dye is injected into a blood vessel in the arm. As the dye travels through the circulatory system, it will eventually reach the eye’s circulation. Photographs are then taken every few seconds to track how the dye flows and illuminates structures inside the eye. ICG is particularly good for examining deep structures in the retina, especially in cases of retinal bleeding where the view is otherwise obscured. Fluorescein angiography is a similar test, and more commonly performed. It looks for problems in the more superficial layers of the retina.