Patient Information

Fundus Fluorescein Angiography (FFA) of the eye


What are these tests?

These simple tests examine the circulation of blood in the back of your eye.

Dye is injected into a vein in your hand or arm. The dye then travels to the blood vessels in your eye. A series of photographs of your eye are then taken. How the eye looks with these dyes will tell us a lot about the condition of your eye.

Fundus Fluorescein Angiography (FFA) involves a yellow dye called fluorescein. It looks at the retina.

Indocyanine Green Angiography (ICG) uses a green dye called indocyanine. It looks at the choroid, which is a layer below the retina.

What is the retina?
The retina is the light-sensitive layer at the back of the eyeball. It converts the image of what we see into electric signals. These signals go to the brain to tell us what we are seeing.

What is the choroid?
The choroid is a layer in the eyeball. It supplies the retina with oxygen and nutrients. It is vital for a healthy retina.

Why are these tests done?

There are many conditions that can affect the circulation of blood in your eye, causing problems with the retina.

These tests help us diagnose certain eye conditions affecting the retina and choroid. They will also guide us to plan the right treatment.

How to prepare for the tests

Sign a consent form.

You will need to have signed a consent form when you were advised by the doctor to have this test done. The doctor will have explained the risks. If you still have any questions on the day of the test, ask any of the team when you arrive.

You must remove your contact lenses before the test.

Tell the nurse or technician when you arrive:

  • if you are or may be pregnant,
  • if you are breast-feeding
  • if you have kidney failure
  • if you have any allergies
  • if you have epilepsy.

The whole test only takes about 30 to 45 minutes. However, you should expect to be in the department for 1 to 2 hours so that we can do the necessary checks before and after the tests.

What happens during the tests

  1. You will be tested on how well you can read letters on a chart.
  2. The pressure in your eye will be measured using a special machine that blows a puff of air against your eye.
  3. You will then be given eye drops that will dilate (widen) your pupil.
    Your vision will be blurry for 4 to 6 hours because of these eye drops.
    You should not drive after the test.
  4. You will be asked to place your chin on a chin rest and your forehead against a support bar to keep your head still during the test.
    You will be asked to keep your eyes wide open while the technician takes images of the inside of your eye.
  5. We will take pictures of the inside of your eye.
  6. After the first group of pictures is taken, the green dye is injected into a vein in your hand by a nurse. This may be followed by the yellow dye if requested by the doctor.
  7. A camera takes a short video and pictures of the inside of your eye as the dye moves through the blood vessels in the back of the eye.
  8. The needle in your vein will be left in your hand for 30 minutes. Once we are certain that you have not suffered any adverse reactions, the needle will be removed.

How will the tests feel?

When the needle is inserted, some people feel slight pain. Others feel only a prick or sting.

The dye can burn and stain the skin if it leaks out during the injection. The burning lasts a few minutes. The stain will fade away in a few days.

While the camera takes the pictures, the bright flashing light can be intense and uncomfortable.


Your vision will be blurry for 6 to 8 hours afterwards. This is because your pupils will be dilated due to the drops put in your eyes.

You cannot drive until this blurry vision has resolved.

You can put contact lenses back in straight away.

The fluorescein dye will cause your skin to appear more yellow and eventually pass out in your urine. Your urine and skin will appear more yellow for a day or two after the test.

Are there any side effects?

A few people suffer an allergic reaction to the fluorescein dye. This can cause a rash and itching. It can be treated with antihistamine tablets.

Other common reactions are nausea, vomiting, breathlessness and fainting.

In rare instances, flash photography may trigger an episode of epilepsy or tonic-clonic seizure.

A severe life-threatening allergic reaction (called ‘anaphylaxis’) is very rare. It affects fewer than 1 in 10,000 people. It can cause swelling of the airways and difficulty breathing. Staff are trained to look out for allergic reactions and how to treat them.

These reactions always take effect within a very short space of time. You will not be allowed to leave the unit until this possibility has passed.

Call NHS 111 or go to your nearest ED (A&E) department if you feel unwell after you go home.


The doctor will review your scans at a later date.

At a follow-up appointment, the doctor will discuss the results with you and make recommendations for any treatment you might need.

Before you leave the eye unit, make sure you have a follow-up appointment. This will be within 4 weeks to review the test results. This could be a telephone appointment or face-to-face.


Royal Eye Unit 020 8546 7711 extension 2835

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