Fig. 1.

Cartoon on optical characteristics explaining the differences between fluorescein (FA) and indocyanine green angiography (ICGA). FA is only able to analyse the fluorescence coming from the retina as the RPE is blocking visible light fluorescence, while ICGA is able to analyse retinal and choroidal near-infrared fluorescence which is not blocked by the RPE. Note, at the level of the choriocapillaris, the schematic drawing shows the physiological egression of the ICG macromolecular complex from the fenestrated choriocapillaris impregnating the choroidal stroma (see Fig. 2), determining the intermediate and late angiographic phases that are important for the evaluation of choroiditis