Fluorescein Angiography: Procedure, Benefits, Risks, and What to Expect

Fluorescein angiography is a specialised imaging test that helps doctors examine blood flow in the retina. It reveals abnormalities invisible to the naked eye, helping in early treatment. 

What is fluorescein angiography?

The retina is the thin, light-sensitive layer at the back of the eye. It works like a camera sensor. It captures light and sending signals to the brain to create images. Without a healthy retina, vision can become blurry or lost. The retina needs a steady blood supply to function properly. Any disruption can lead to vision problems. Fluorescein angiography is an advanced imaging technique that helps detect such issues. It uses a special dye and a camera to highlight blood flow in the retina.

During the eye angiography test, a fluorescent dye is injected into a vein, usually in the arm. As the dye circulates through the blood vessels, a series of images are taken. These images help doctors identify leaks, blockages, or abnormal growths. Conditions such as diabetic retinopathy, choroidal neovascularisation in age-related macular degeneration (AMD), and retinal vein occlusion can be diagnosed using this method.

How do I prepare for fluorescein angiography?

Preparation for fluorescein angiography is simple but essential. In some cases, doctors may ask you to avoid food and drinks for a few hours before the test. 

Patients should inform their doctor about any allergies, medications, or existing health conditions. While fluorescein dye is eliminated through the kidneys, it is generally safe for most patients, including those with mild kidney disease. 

Wearing comfortable clothing is recommended. The test involves sitting still while images are taken, so ease of movement is important. Patients should ideally arrange for someone to drive them home after the test. Pupil dilation causes temporary light sensitivity, making it unsafe to drive immediately after the procedure.

How is angiography for the eyes performed?

The fluorescein angiography procedure is conducted in a well-lit examination room, with lighting adjusted as needed for imaging. First, eye drops are applied to dilate the pupils. This allows clearer imaging of the retina. The patient sits in front of a specialised camera, resting their chin to keep the head steady.

A small needle is inserted into a vein, usually in the arm. The fluorescein angiography dye is injected and circulates through the bloodstream, including the retinal blood vessels. Within seconds, the dye highlights the retinal blood vessels. A rapid series of high-resolution images captures the flow, helping doctors detect abnormalities.

The entire test takes about 10 to 15 minutes. Patients may notice a warm sensation throughout the process as the dye spreads. Some might also see a temporary yellow tint in their vision. 

What to expect during fluorescein angiography?

The procedure is quick, but certain sensations may feel unusual. When the fluorescein angiography dye enters the bloodstream, a warm flush might spread through the body. Some patients experience a brief metallic taste in their mouth. These effects fade within minutes.

Bright camera flashes accompany the imaging process. Since pupils are dilated, these flashes may feel intense. However, keeping the eyes open and steady ensures clear images. 

What to expect after fluorescein angiography?

Once the test is complete, the effects of the fluorescein angiography dye gradually wear off. Blurred vision may persist for a few hours due to pupil dilation. Bright lights may seem harsh, so sunglasses can help ease discomfort.

A common temporary effect is yellowish skin or urine. This happens because the body eliminates the dye naturally, usually within 24 hours. 

Most patients can resume normal activities after the test. However, driving should be avoided until vision fully clears. If dizziness or nausea occurs, resting for a while helps. 

What are the risks of fluorescein angiography?

The fluorescein angiography procedure is generally safe, but like any other medical test, it carries some risks. Most reactions are mild and temporary. Some patients experience slight nausea after the dye injection. This usually fades within minutes.

Allergic reactions are rare but possible. Symptoms may include itching, skin rash, or mild swelling. In extremely rare cases, severe reactions like breathing difficulty can occur. 

In very rare cases, patients may experience vasovagal reactions (fainting) or severe allergic responses requiring immediate medical attention.

What are the side effects of fluorescein angiography?

Most patients complete the fluorescein angiography procedure without complications. However, some side effects may appear temporarily. A common one is skin discolouration. The dye gives the skin and urine a yellowish tint, but this fades within a day.

Mild nausea can occur immediately after the injection. It usually passes quickly. Some patients report a brief metallic taste in the mouth. This is harmless and disappears within minutes.

Rarely, severe allergic reactions or vasovagal responses may follow the test. Resting for a short while helps in most cases. If an allergic reaction develops, such as itching or swelling, alert the medical staff.

Conditions Diagnosed by Fluorescein Angiography

Doctors use fluorescein angiography to detect various eye conditions affecting the retina and blood vessels. The test provides a detailed view of retinal and choroidal circulation in the eye.

• One common condition identified is diabetic retinopathy. In diabetes, damaged retinal capillaries and abnormal new vessel growth (neovascularisation) can cause fluid leakage or bleeding, damaging vision over time. 
• Choroidal neovascularisation in age-related macular degeneration (AMD) is another condition examined through this method. It affects the central vision, making tasks like reading difficult. Fluorescein angiography helps doctors see abnormal blood vessel growth beneath the macula, the part of the eye responsible for sharp vision.
• Other conditions include retinal vein occlusion and complications related to hypertensive retinopathy. Early detection allows timely medical intervention, reducing the risk of severe vision loss.

Understanding Fluorescein Angiography Results

The images captured during fluorescein angiography provide crucial insights into eye health. They help doctors assess blood flow in the retinal and choroidal vessels and spot abnormalities that might not be visible in a routine eye exam.

If the results show normal circulation, it means the retinal blood vessels are functioning well. However, blocked, leaking, or swollen vessels indicate underlying problems. Conditions like macular edema, diabetic retinopathy, or retinal vein occlusion can be diagnosed based on these findings.

Doctors examine the patterns of dye movement to determine the severity of an issue. Early leaks suggest weak blood vessels, while slow circulation may point to blockages. These results guide treatment decisions, ensuring timely care to prevent further damage.

Conclusion

Vision is one of life’s greatest gifts. Protecting it requires timely detection of eye conditions. Fluorescein angiography plays a vital role in diagnosing retinal diseases early, giving doctors a clear picture of blood flow in the eye. This test helps prevent vision loss by guiding precise treatments.

Most patients undergo the eye angiography test without complications. Mild fluorescein angiography side effects like temporary skin discolouration or nausea fade quickly. The benefits, however, are long-lasting.