What is a Fluorescein Angiography?
Fluorescein angiography is a test that helps to diagnose certain retinal diseases and problems. Fluorescein is a special fluorescent dye, and in a fluorescein angiogram, a patient is injected with dye, usually in the arm. The dye moves through the patient's bloodstream, to the eye and through the blood vessels of the retina, the portion of the eye responsible for vision. Characteristic "flow patterns" are indicative of certain retinal problems. The ophthalmologist or the technician will take photographs of these patterns for later reference.
When is an Fluorescein Angiography used?
One example of the type of problems that a fluorescein angiogram can reveal is diabetic retinopathy. Diabetes affects the eye in many ways. For example, in background diabetic retinopathy, diabetes can cause certain blood vessels to leak fluid or blood to the retina, causing vision abnormalities. In a fluorescein angiogram from a patient with background diabetic retinopathy, areas near the leaking vessels are saturated with fluorescein. In proliferative diabetic retinopathy, new blood vessels grow in parts of the retina required for visual function, resulting in vision abnormalities. A fluorescein angiogram would show these blood vessels as they course across the retina disturbing the light sensitive tissues required for accurate vision.
Other diseases besides diabetes can be monitored using fluorescein angiography. Certain types of age-related macular degeneration in which blood vessels grow underneath the retina and retinal vein occlusion where the retinal vein becomes blocked and the retina becomes infused with blood are other examples. If the precise location of these problems can be determined, then an ophthalmologist can consider laser as a possible treatment option.
Are there side-effects to a fluorescein angiography?
After a fluorescein angiogram, the patient's skin may gain a yellowish tint and the patient's urine may become dark orange as the fluorescein dye is filtered from the bloodstream. This may last up to 24 hours after the test has concluded. In rare cases, patients have minimal nausea and staining of skin near the injection site. It is even rarer that a patient will have an allergic reaction to the dye; these reactions can vary from skin rashes to anaphylactic, life-threatening reactions.