Fluorescein angiography, also called eye angiography and retinal photography, is a diagnostic eye test that utilizes a specific fluorescent dye and special camera to take photographs of the retina, the light responsive tissue located in the back of the eye. This specialized procedure is primarily used to determine if the retinal blood vessels are receiving adequate circulation. Fluorescein angiography can also be performed to secure a permanent record of the retinal vessels of the eye, to assist a physician in the confirmation of a diagnosis, or to supply proper treatment guidelines.
The fluorescein angiography process begins when eye drops are inserted into the eye to encourage pupil dilation. The first series of photographs are then taken of the inside of the eye. Next, a yellow, water-soluble dye called fluorescein sodium will be injected into a vein in the arm or hand. A highly fluorescent chemical compound, fluorescein pulls in blue light with fluorescence. After the fluorescein injection, a special camera which emits a blue light takes another group of photographs as the dye travels through the blood vessels of the retina. The scans are taken rapidly, over a period of 60 seconds. Additional scans may be taken up to 20 minutes after the fluorescein is injected.
An invasive procedure, 5 to 10% of fluorescein angiography patients report adverse reactions, with nausea and vomiting being the most common complaints. Many patients report moderate pain when the needle is inserted into the arm, and also experience a warm sensation as the dye enters the body. These symptoms, however, are fleeting. After the injection of fluorescein dye, the skin may have a yellowish tone for several hours. Patients will also experience a change in urine color a day or two after the procedure, with urine darker and potentially orange in color. Patients should be prepared to experience blurred vision for up to twelve hours after fluorescein angiography.
Fluoscein angiography that produces normal results means that there are no leakages or blockages in the vessels of the retina, and that the vessels appear to be of typical size. An abnormal fluorescein angiography result may be due to many factors, including diabetes, macular degeneration, optic disk swelling, and circulatory problems. Both diabetes and macular degeneration can cause the blood vessels of the retina to leak fluid or blood. Fortunately with laser treatment, the abnormalities of the retina due to these diseases can be successfully repaired, and treatment results can be monitored with further fluorescein angiography procedures.