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Diagnostic Testing: Retinal Angiography

Fluorescein Angiography

An angiogram is a diagnostic procedure used in ophthalmology to image the blood vessels of the retina. It involves inserting a needle into a vein, usually in the arm or back of the hand, and injecting a contrast dye. As the dye circulates through the bloodstream, images of the retina are taken using specialised digital cameras and scanning laser technology. The procedure usually takes around 5 minutes, and the results are available immediately.The procedure is safe, with a low risk of severe adverse reactions.Fluorescein dye is most often used for retinal angiography. Fluorescein is a yellow-coloured dye that glows when excited by a certain wavelength of light, which allows for imaging of the retinal circulation.

Fluorescein angiography is useful in the diagnosis and monitoring of conditions such as age-related macular degeneration, diabetic eye disease, and retinal vascular occlusions. 

Indocyanine Green Angiography

Indocyanine green (or ICG), an iodine-based contrast dye, glows when excited by a certain wavelength of light. It is often used in conjuction with fluorescein. As in fluorescein angiography, the dye is injected through a needle into a vein. The procedure can take up to 10 minutes, and the results are available immediately.

ICG is used to assess the choroid, the layer behind the retina, and can be used in the diagnosis and management of conditions affecting this layer. These include central serous retinopathy (CSR) and types of age-related macular degeneration such as polypoidal choroidal vasculopathy.