Fluorescein angiography
Fluorescein angiography (FA), fluorescent angiography (FAG), or fundus fluorescein angiography (FFA) is a technique for examining the circulation of the retina and choroid (parts of the fundus) using a fluorescent dye and a specialized camera. Sodium fluorescein is added into the systemic circulation, the retina is illuminated with blue-green light at a wavelength of 490 nanometers, and an angiogram is obtained by photographing the fluorescent green light that is emitted by the dye.