Question

Principles of Fundus Fluorescein Angiography (FFA).

Hint:

FFA is an essential diagnostic tool in retinal and choroidal diseases, especially for identifying areas of retinal leakage and ischemia.

Answer 1

Fundus Fluorescein Angiography (FFA) is a diagnostic procedure used to visualize the blood vessels of the retina and choroid. It involves the use of fluorescein dye injected into a vein to evaluate the circulation in the retina.

Step 1: Introduction to FFA:
1. Fluorescein Dye: A fluorescent dye (fluorescein) is injected intravenously. This dye binds to plasma proteins and circulates through the bloodstream, eventually reaching the retinal and choroidal vasculature.
2. Camera Setup: A specialized camera with a blue light source is used to illuminate the retina. The camera detects the fluorescence emitted by the dye when exposed to blue light, allowing visualization of the blood vessels.

Step 2: Phases of FFA:
1. Arterial Phase: This occurs within the first seconds after dye injection, showing the dye's movement through the retinal arteries.
2. Venous Phase: This follows shortly after, showing the dye flowing through the venous system.
3. Late Phase: The late phase reveals the leakage of dye from the retinal vessels, helping to detect abnormalities such as hemorrhages, exudates, and macular edema.

Step 3: Indications for FFA:
1. Diabetic Retinopathy: FFA helps assess the severity of diabetic retinopathy and detect retinal ischemia.
2. Macular Diseases: It is useful in diagnosing macular edema, macular degeneration, and retinal vein occlusion.
3. Vascular Occlusions: FFA can help identify retinal artery or vein occlusions by visualizing areas of ischemia and retinal damage.