FLUORESCEIN & ICG ANGIOGRAPHY

What is Fluorescein and Indocyanine Green Angiography?

Fundas Fluorescein Angiography is a test that provides further information about problems at the back of the eye by photographing the flow of blood through it. It uses a dye called fluorescein to do this. This angiogram can show leaking blood vessels in the macula and can show up any small leaks that could not otherwise be detected.

Indocyanine Green Angiography, also referred to as ICG, is similar to fluorescein angiography but uses a different dye which can image deeper layers of the retina.

Why Has The Test Been Recommended?

A Fluorescein Angiogram and/or ICG may be recommended by your Ophthalmologist if any irregularities of the retina are discovered at your consultation.

Fluorescein Angiograms and ICG are used in:

determining the need for treatment for certain eye diseases
guidance during laser surgery
monitoring the effects of laser surgery, and
monitoring any changes in your eye over a period of time.

What Conditions Can The Test Diagnose?

Fluorescein angiography and ICG are used to diagnose certain eye conditions, determine if treatment is needed, and plan or guide treatment.

The photographs can then help your specialist diagnose and monitor eye diseases such as:

Macular Degeneration,
Diabetic Retinopathy,
Retinal Vein Occlusions,
Cystoid Macular Oedema,
Retinal Vascular Diseases.

What Information Can The Test Show?

Cause of leaking blood vessels in the eye
The type of Macular Degeneration
The location of areas of leakage
Where to place laser

Preparation For a Fluorescein Angiography

It is very important to discuss any health conditions that you have, all the medications that you are taking, and especially any allergies to medications that you have had in the past. It is preferred that you bring this information as a letter from your doctor.

If you have had a previous fluorescein angiogram, mention this as well.

You do not need to fast for this test.

Please advise the staff prior to the test being commenced if you are or suspect you may be pregnant. Fluorescein is reported to be safe in pregnancy but it is preferable to avoid this test in pregnant patients if possible.

What Happens During a Fluorescein Angiography?

The test takes about 30 minutes, but allow one to two hours for the necessary pre- and post-test checks.

During the test

A water-soluble dye called Fluorescein and if needed ICG, is injected into a vein in your arm, where it travels through the body reaching the eye.
A special camera is used to take multiple photographs of the back of your eyes as the dye passes through the blood vessels. This provides information about the retina and nearby tissues.

Depending on the procedure employed, this may involve bright flashes of light to highlight abnormalities that may not be detectable by examining the eye alone.

Diagnostic Pathway

There are two pathways

Fluorescein Angiography - Most angiograms are done using the Fluorescein dye. Your skin may turn slightly yellow for several hours after the Fluorescein dye is injected. The dye will be flushed out of the system through your urine, which can be a very orange colour for up to 24 hours; drinking water will flush out the dye faster.
Indocyanine Green Angiography - The Indocyanine Green (ICG) angiogram is a similar but less frequently performed investigation. An ICG angiogram can sometimes locate abnormal choroidal vessels better than a fluorescein angiogram however an ICG is not recommended for patients with an allergy to iodine.

Risks Associated With Fluorescein Angiography

Thousands of fluorescein angiograms are performed every year in Australia and New Zealand. The chance of adverse effects is low, but as with any medical procedure, there are some risks involved.

Possible complications with the test can include:

Vein Damage - the cannula used to inject the dye into the arm can damage a fragile vein, causing burning and yellowing of the skin around the injection point. This yellowing on the skin will go away after a few days.
Nausea - as the dye is injected into the vein, some patients experience nausea. This passes after a few seconds.
Allergy - reactions to the dye are rare. Rashes or skin irritations are treated with oral or injected antihistamines.
The most severe allergic reaction is called anaphylaxis, which is very rare but may be life-threatening.
Very rarely patients may experience breathing difficulty or heart rhythm disturbances, which can be severe and even cause death.

If you have any questions please ask prior to the test.