The retina is a photo-sensitive layer present on the interior of the eye. Light entering the eye is focused on the retina where it is converted to nerve signals that reach your brain for interpretation of the image. Blood to the retina is supplied by an underlying vascular layer called the choroid. The blood supply can be studied by an imaging technique called angiography, which uses fluorescein or indocyanine green dye.
What conditions can this procedure evaluate?
Angiography is helpful in diagnosing a variety of conditions affecting retinal and choroid blood supply such as macular degeneration or oedema, retinal vein occlusion and diabetic retinopathy. It is also used to guide laser surgery.
How is the procedure performed?
Fluorescein or indocyanine is injected into the blood stream. As the dye passes through the retinal and choroid blood vessels, a special camera is used to obtain photographs. Fluorescein is more useful for studying retinal vessels while indocyanine helps identify the deep choroid blood vessels.
What are the side effects or risks associated with the procedure?
Side effects are rare, and may include temporary discolouration, rash or itching of the skin, breathing problems, nausea, dark orange urine and burning at the injection site.