Fundus Fluorescein Angiography (FFA)
Fluorescein angiography is a diagnostic test which uses a special camera to take a series of photographs of the retina. A special water-soluble fluorescein dye is injected into a vein in the arm. The dye travels through the veins and into the arteries as it circulates throughout the body. As the dye passes through the blood vessels of the retina, the special camera flashes a blue light into the eye and takes multiple black and white photographs of the retina. The dye appears as white in the photographs.
If the blood vessels are abnormal, the dye is seen leaking into the retina. Areas without blood supply dark due to the absence of dye. New vessels on or under the retina will leak dye profusely.
Why is FFA done?
- To help the doctor confirm a diagnosis.
- To provide guidelines for treatment.
- To keep a permanent record of your retinal condition
What is the procedure?
- The test is performed in the OPD
- Your pupils will be dilated with eye drops.
- An injection of yellow dye is given into a vein in your arm.
- A series of photographs (20-40) is taken as the dye enters the eye.
- The test takes about 5-10 minutes and results are immediately available
What are the special instructions?
It is best not to eat something 2 hours before the test. All medications must be taken as usual. The procedure can be performed even of the sugars are not controlled. As the pupils will be dilated you may have blurred vision for 3-4 hours and may need to arrange your schedule and arrange for a driver.
How does the dye affect the body and are there side effects?
After the fluorescein dye is injected, your ‘skin may turn yellowish’ for several hours. This color disappears as the kidneys filter the dye from your body. Because the dye is removed by the kidneys, your ‘urine will turn dark yellow/green’ for up to 24 hours following fluorescein angiography. Some individuals may experience slight nausea during the procedure, but this usually passes within a few seconds. If the dye leaks out of a fragile vein during the injection, some localized burning and yellow staining of the skin may occur. This burning usually lasts only a few minutes and the staining will go away in a few days. Allergic reactions to fluorescein dye are rare. If they occur, they may cause a skin rash and itching. This is usually treated with oral or injectable antihistamines/steroids, depending on the severity of the symptoms. Extremely rarely, severe allergic reactions (anaphylaxis) can occur and be life threatening.
NOTE:
Please notify the doctor if you have a tendency of allergies, asthma or severe kidney or heart disease or very high blood pressure. These do not mean that the test cannot be done but special care can be taken. FFA must be avoided in pregnant women and those with previous allergy to the dye.