What is a fundus fluorescein angiogram (FFA)?

Fundus Fluorescein Angiography (FFA): Diagnostic Imaging of Retinal Vasculature

Fundus fluorescein angiography is a valuable diagnostic imaging technique that uses intravenous sodium fluorescein dye to evaluate retinal and choroidal circulation, helping to identify vascular abnormalities, areas of ischemia, and leakage in various retinal disorders. 1, 2

Procedure Overview

• Fluorescein sodium is injected intravenously (typically 500 mg for adults or 7.7 mg/kg for children) and circulates through the ocular vasculature 3
• The dye responds to blue light (465-490 nm wavelength) and emits yellowish-green fluorescence (520-530 nm), which is captured by a specialized fundus camera 3
• Luminescence appears in retinal and choroidal vessels within 7-14 seconds after injection, allowing visualization of vascular structures 3
• Sequential photographs are taken to document different phases of dye circulation through retinal and choroidal vasculature 1

Clinical Applications

• Evaluates the extent of vascular occlusions (retinal vein or artery occlusions) 1
• Assesses the degree of retinal ischemia (ischemic vs. nonischemic) 1
• Identifies macular capillary nonperfusion that may explain vision loss 1
• Distinguishes collateral vessels (no late leakage) from retinal neovascularization (shows late leakage) 1
• Detects areas of untreated retinal capillary nonperfusion that may explain persistent neovascularization 1
• Localizes leaking microaneurysms or areas of capillary dropout 1

Comparison with Other Imaging Modalities

• While optical coherence tomography (OCT) has become the primary tool for evaluating macular edema, FFA remains valuable for assessing vascular perfusion 1
• Recent studies show that optical coherence tomography angiography (OCTA) is similar to FFA in detecting capillary nonperfusion and vascular abnormalities, but OCTA is currently limited by image artifacts and field of view 1
• Ultrasonography is preferred when media opacity prevents adequate visualization of the retina 1

Safety Considerations

• FFA is generally safe but carries potential risks that require informed consent 1
• Severe medical complications are rare but can occur, including death (approximately 1 in 200,000 patients) 1, 4
• Common adverse reactions include transient nausea and vomiting 5
• Rare adverse events include vasovagal reactions, cardiac or respiratory effects, and anaphylaxis 5
• Each angiography facility should have an emergency care plan and protocol to manage risks and complications 1
• Special considerations for pregnant women: fluorescein crosses the placenta, and while no detrimental effects on the fetus have been documented, FFA should be performed only when absolutely necessary 1

Administration Protocol

• Inject the dose over 5-10 seconds into the antecubital vein, taking precautions to avoid extravasation 3
• A syringe with fluorescein may be attached to transparent tubing and a 23-gauge butterfly needle 3
• Draw the patient's blood to the hub of the syringe to create a small air bubble separating the blood from the fluorescein 3
• With room lights on, slowly inject blood back while watching for signs of extravasation 3
• When extravasation is ruled out, turn off room lights and complete the fluorescein injection 3

Evolving Role in Clinical Practice

• As anti-VEGF agents and intraocular corticosteroids have increased for treating macular edema, the use of grid laser treatment has decreased, reducing the need for FFA 1
• However, FFA remains a valuable tool for ophthalmologists diagnosing and treating retinal vascular disease 1
• Wide-field FFA is being used to evaluate peripheral nonperfusion, though current data on its benefits are still inconclusive 1

Nursing Care Considerations

• Nurses responsible for intravenous administration should follow an individualized care plan 6
• Monitoring for adverse reactions and having emergency equipment readily available are essential parts of the procedure 4

FFA continues to be an important diagnostic tool in ophthalmology despite the emergence of newer imaging technologies, providing unique information about retinal and choroidal circulation that guides clinical decision-making in various retinal disorders.