Fluorescein angiography of the eyes

We have blood vessels in every part of our bodies, including our eyes. Angiography is a way of taking a picture of the blood vessels and fluorescein is a dye that makes the blood vessels more obvious. The pictures let the doctors confirm or rule out certain eye conditions or monitor eye treatment. There are several different types of angiography but this page from Great Ormond Street Hospital (GOSH) is only about fluorescein angiography of the eyes.Vision involves various parts of the eye. When light enters the eye through the pupil, tiny muscles attached to the lens squeeze or relax to focus the light onto the retina. This is the lining at the back of the eye. The image is upside down at this point. Signals from the retina travel down the optic nerve to the brain, which interprets them and automatically turns the image the right way up again.

The retina is supplied with blood and oxygen through a network of tiny blood vessels. Any damage to the blood vessels affects how the retina works, often producing a ‘blind spot’. Fluorescein angiography is a way of looking at these blood vessels to see if there are any abnormalities or damaged areas. It is used to make a diagnosis, plan treatment or monitor the effects of a treatment your child might already be receiving.

Fluorescein is a dye that fluoresces (glows) under blue light. When fluorescein is swallowed, it travels to the blood vessels supplying the retina at the back of the eye. This takes up to 30 minutes or so. When a blue light is shone on the area, the blood vessels glow so are easier to see and photograph. This shows blood flow to the retina and any abnormal or damaged blood vessels.

If your child (or a close relative) has ever had a severe reaction to injected dyes, please tell us as soon as possible. We may have to find a different way of looking at the blood supply in your child’s eyes.

Fluorescein can stain the teeth so we will give your child a straw to use to drink the juice or squash. Staining is temporary and fades with good tooth brushing over the next few days.

Skin discolouration occurs within a few minutes of swallowing the fluorescein, turning it a yellow colour. This gradually fades over 6 to 12 hours as the dye is absorbed by the body. The dye is removed by the kidneys and passes out of the body in urine (pee). This means that your child’s urine may glow for 24 to 36 hours after the angiography. These effects are caused by the chemical make-up of the fluorescein but are harmless and temporary.

Rarely, some people have a severe allergic reaction to fluorescein. Signs of a severe allergic reaction include skin rashes and itching, high temperature, shivering, redness of the face, a feeling of dizziness or a headache, as well as shortness of breath or chest pain.

We will monitor your child for 60 minutes after they have swallowed the dye. If they show any signs of an allergic reaction, please let the doctor or nurse know immediately.

When you and your child have checked in at the Eye Clinic, the clinic assistants will weigh and measure your child as usual. The amount of fluorescein needed is worked out according to your child’s weight.

A member of the eye team will tell you all about the test and answer any questions. They will ask you to give your permission for the test by signing a consent form.

Important

The person bringing your child for the test should have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the test.

The clinic assistant may put some drops in each eye – these make the pupil at the front of the eye widen so more light can enter the eye and the photographs are more accurate.

Next we will give your child a drink of ice cold juice or squash which contains the dose of fluorescein dye. The fluorescein does not taste very nice so we suggest they drink it down in one go. We will give them another drink afterwards to take away the taste.

The photographer will take a series of photographs over the next 30 minutes or so, as the dye travels to the blood vessels in the eye.

When they have enough photographs, you will be able to go – we advise waiting in the department for about half an hour so we can make sure your child has not had an allergic reaction to the dye. After this you can take your child home unless you have any other appointments or scans booked.

Your child should drink plenty of fluids after the test. This will help their body flush the dye out of their system.

Do not be alarmed if their urine is a different colour or glows, this shows that the dye is leaving their body as expected.

Your child’s skin may develop a yellow tinge in the hours after the test – again this is just the dye travelling through your child’s body. The yellow tinge will disappear over the next few hours.

We will make sure that the results are ready in time for your next appointment with the eye doctor, even if this is the same day as the test.