Fluorescein Angiography: Illuminating the Eye’s Circulatory System

Since the late 1960s, fluorescein angiography has reshaped how eye doctors diagnose and treat retinal diseases. Ophthalmologists use it to detect irregularities within retinal blood vessels before they progress and affect vision. Today, it continues to guide treatment decisions and is central to modern retinal care.

What Is Fluorescein Angiography, and Why Do Doctors Still Use It?

Fluorescein Angiography (FA or FAG) is a diagnostic procedure that uses a contrast dye and a camera to create detailed images of blood flow through the blood vessels in the back of the eye, particularly in the retina and choroid [1]. It “maps” the eye’s circulatory system by showing areas of healthy blood flow and illuminating issues that may signal conditions like diabetic retinopathy and macular degeneration.

Even though decades have passed since its invention, doctors continue to use fluorescein angiography because it’s still one of the most reliable tools for diagnosing and monitoring retinal diseases. Despite advancements in imaging technology, it still captures a high level of detail that newer methods often cannot match.

How Does Fluorescein Angiography Work?

The process of fluorescein angiography might sound complex, but it’s based on a simple principle: making blood vessels shine bright. Here’s the procedure’s step-by-step breakdown:

1. The eye doctor injects a small amount of contrast dye into one vein, usually in the arm.
2. The dye makes it way through the patient’s bloodstream and into the blood vessels in the eye within seconds.
3. As the dye flows through the retina’s blood vessels, a digital fundus camera takes rapid sequences of photographs.
4. The camera uses blue light to illuminate the retina, which causes the fluorescein to “fluoresce” and emit light with a longer wavelength.
5. A filter in the camera blocks all light except the fluorescent glow, which results in clear images of the highlighted blood vessels. [2].

The process captures a series of images that track the dye as it moves through the blood vessels, ultimately revealing how blood flows in the eye and if there are any blockages, leaks, or abnormal vessel growth.

What Are the Advantages of Fluorescein Angiography Over Other Imaging Tests?

Here are some of the benefits of using fluorescein angiography in modern eye care:

1. Detects Vascular Abnormalities

FA can reveal problems with blood vessels that aren’t visible through other examination methods. It can show leaking blood vessels, blocked vessels, or abnormal new vessel growth [3].

2. Guides Treatment Decisions

The detailed images from FA help eye care professionals decide on the best treatment. In cases of diabetic retinopathy, FA pinpoints leaking blood vessels to guide laser treatment [4].

3. Monitor Disease Progression

For patients with chronic eye conditions, FA tracks changes over time with high accuracy. It proves especially effective in managing diseases like age-related macular degeneration (AMD) and diabetic retinopathy, allowing doctors to make timely and accurate treatment decisions [5].

4. Evaluating Treatment Effectiveness

After treatments such as laser therapy or injections for retinal conditions, FA can help assess how well the treatment choice is working by showing changes in blood flow or leakage [6].

What Conditions Can Fluorescein Angiography Help Diagnose?

Fluorescein angiography is beneficial in diagnosing and managing a variety of eye conditions, including:

1. Diabetic Retinopathy: FA can reveal leaking blood vessels, areas of poor circulation, or abnormal new blood vessel growth.
2. Age-related Macular Degeneration (AMD): FA helps identify the type of AMD and guides treatment decisions.
3. Retinal Vein Occlusion: FA can show blocked veins and areas of poor blood flow in the retina.
4. Macular Edema: The procedure can highlight areas where fluid is leaking into the macula.
5. Choroidal Neovascularization: FA is excellent at detecting abnormal new blood vessel growth under the retina.
6. Certain Types of Eye Tumors: Some eye tumors have characteristic blood flow patterns that FA can expose [7].

What to Expect During a Fluorescein Angiography Procedure

If your eye doctor in Sun City, AZ, recommends fluorescein angiography, here’s what you can expect:

1. The doctor will dilate the pupils using tropicamide eye drops.
2. The doctor will inject a very small amount of dye into a vein in your arm. You might feel a warm sensation.
3. As the dye reaches your eyes (usually within 10 to 15 seconds), the camera will take a series of photos using a special camera. You’ll see a bright flash with each photo.
4. The procedure usually takes about 10-15 minutes, though you may need to wait about 30 minutes after the injection for a final set of images.

It’s important to note that your skin and urine may appear yellow for up to 24 hours after the procedure as your body eliminates the dye [8].

Are There Any Risks or Side Effects?

Fluorescein angiography is generally safe, but like any medical procedure, it carries some risks. Common side effects include:

• Temporary yellowing of skin and urine
• Nausea (usually brief)
• Temporary blurred vision due to dilated pupils

Rare but more alarming side effects can include allergic reactions to the dye. It’s crucial to inform your eye care professional of any allergies or medical conditions before the procedure [9].

Fluorescein Angiography vs. Other Imaging Techniques

While fluorescein angiography reveals important details about the eye’s vascular system, it sometimes works best alongside other imaging techniques to fully understand eye health. For example:

• Optical Coherence Tomography (OCT) generates detailed cross-sectional images of the retina’s layers.
• Doctors often use Indocyanine Green Angiography (ICGA) with FA to check the choroid and gain deeper insights into the eye’s vascular layers.
• OCT Angiography is a newer, non-invasive technique that can image blood vessels without dye injection, though it may not replace FA in all cases [10].

Each technique has its strengths, and your eye care professional will determine which is most appropriate for your specific situation.

The Future of Fluorescein Angiography

Despite being in use for over 60 years, fluorescein angiography continues to evolve. Some exciting developments include:

1. Ultra-widefield FA: This approach enables imaging of a much larger area of the retina in a single photograph.
2. Integration with OCT: FA/OCT systems capture both blood flow and structural details. Doctors can use this combined data to assess eye health more comprehensively.
3. Digital Analysis: Advanced software can now analyze FA images and potentially aid in faster, more accurate diagnoses [11].

The Bottom Line

Fluorescein angiography improved retinal imaging by making blood vessels in the eye visible in vivid detail. This procedure detects abnormalities like blockages, leakage, or abnormal growths, which are often the first signs of serious eye diseases.

For patients, understanding fluorescein angiography helps clarify its role in a thorough eye examination. When doctors recommend this test, it delivers specific information about retinal health, and these results can guide treatment decisions.

Partner with Arizona Retinal Specialists to leverage these advanced technologies and maintain healthy vision for years to come. Contact us at 623-474-3937 to schedule a consultation.

References:

1. Novotny, H. R., & Alvis, D. L. (1961). A method of photographing fluorescence in circulating blood in the human retina. Circulation, 24, 82-86.
2. Marmor, M. F., & Ravin, J. G. (2011). Fluorescein angiography: insight and serendipity a half century ago. Archives of Ophthalmology, 129(7), 943-948.
3. Gass, J. D. M. (1967). Pathogenesis of disciform detachment of the neuroepithelium: I. General concepts and classifications. American Journal of Ophthalmology, 63(3), 573-585.
4. Early Treatment Diabetic Retinopathy Study Research Group. (1991). Early photocoagulation for diabetic retinopathy: ETDRS report number 9. Ophthalmology, 98(5), 766-785.
5. Yannuzzi, L. A., et al. (1992). Fluorescein angiography complication survey. Ophthalmology, 99(3), 327-337.
6. Holz, F. G., et al. (2003). Progression of geographic atrophy and impact of fundus autofluorescence patterns in age-related macular degeneration. American Journal of Ophthalmology, 135(1), 45-53.
7. Haining, W. M., & Lancaster, R. C. (1968). Advanced Techniques of Fluorescein Angiography. Archives of Ophthalmology, 79(1), 10-15.
8. Kwan, A. S., Barry, C., McAllister, I. L., & Constable, I. (2006). Fluorescein angiography and adverse drug reactions revisited: the Lions Eye experience. Clinical & Experimental Ophthalmology, 34(1), 33-38.
9. Kwiterovich, K. A., et al. (1991). Frequency of adverse systemic reactions after fluorescein angiography: results of a prospective study. Ophthalmology, 98(7), 1139-1142.
10. Spaide, R. F., Klancnik, J. M., & Cooney, M. J. (2015). Retinal vascular layers imaged by fluorescein angiography and optical coherence tomography angiography. JAMA Ophthalmology, 133(1), 45-50.
11. Tan, C. S., et al. (2016). Optical coherence tomography angiography and indocyanine green angiography for corneal neovascularisation. British Journal of Ophthalmology, 100(6), 749-753.