Fluorescein angiography

What is fluorescein angiography?

Fluorescein angiography is a test that uses a yellow dye and a special camera to take pictures of the blood vessels at the back of your eye (the retina). It shows your specialist how well blood is flowing through these vessels and highlights any that are damaged, leaking or blocked.

Why might I need fluorescein angiography?

You might be offered fluorescein angiography to help diagnose or monitor eye conditions that affect the blood vessels in your retina, such as:

• age-related macular degeneration
• diabetic retinopathy, damage to the retina caused by diabetes
• blockages in the retinal veins
• swelling of the macula, the central part of the retina
• inflammation at the back of the eye, such as uveitis
• eye cancer, to help with diagnosis or to check how well treatment is working

It's also used to plan laser treatment and to track how an eye condition changes over time

What are the benefits of fluorescein angiography?

Fluorescein angiography gives your specialist a detailed, moving picture of blood flow in your retina that other tests, such as a standard photograph of your eye, cannot show. This helps them reach an accurate diagnosis, decide whether treatment is needed, and target it more precisely if it is.

Are there different types of fluorescein angiography?

Fluorescein angiography is sometimes carried out alongside a related test called indocyanine green (ICG) angiography, which uses a different dye and infrared light to look at the layer of blood vessels underneath the retina, called the choroid. Your doctor will tell you if you need one or both tests. If you need both, they can usually be done in the same appointment.

How do I prepare for fluorescein angiography?

• you can usually eat, drink and take your regular medication as normal; your nurse will tell you beforehand if anything needs to change
• around 15 to 30 minutes before the test, drops are put in your eyes to widen (dilate) your pupils, which may sting briefly
• you'll need to remove contact lenses beforehand, so it may help to bring your glasses
• your vision will be blurred and sensitive to light for several hours afterwards, so you won't be able to drive yourself home; arrange for someone to bring you or take you home, and bring sunglasses if you have them
• tell the nurse or doctor beforehand if you have any allergies, take blood thinners, or have kidney problems, as these can affect whether you can have the test

What happens during fluorescein angiography?

1. A nurse checks your vision, then puts drops in your eyes to dilate your pupils. A second set of drops may follow after about 10 minutes.
2. You're shown to a room where a small tube (cannula) is inserted into a vein in your hand or arm.
3. You sit at a special camera with your chin and forehead supported, and some preliminary photographs are taken.
4. The dye is injected through the cannula. It takes only a few seconds to reach your eye, and you may feel warm, flushed or briefly nauseous.
5. A series of photographs is taken as the dye passes through the blood vessels in your retina, with bright flashes of light.
6. After a short rest, a further set of photographs may be taken to check for any pooling of the dye in the eye.
7. The cannula is removed and a dressing is applied before you go home.

The test itself usually takes between 10 and 30 minutes, though you should expect to be at the hospital for up to 2 hours in total, to allow time for your pupils to dilate and for a short rest afterwards.

What happens after fluorescein angiography?

Your vision will stay blurred and sensitive to light for several hours, and this can last up to 24 hours, so you'll need someone to take you home. It's common for your urine to turn bright yellow or orange for 1 to 2 days, and your skin may look slightly yellow for a few hours. This is harmless and is just the dye leaving your body.

You can eat and drink normally, and most people return to their usual activities the next day. Rest when you get home and try to avoid reading or screens if your eyes feel tired or sensitive. You may have some bruising where the cannula was, which settles over the next few days.

Your specialist can often discuss the findings with you on the same day, though a full written result may follow later.

What are the risks of fluorescein angiography?

• Mild reactions: skin or urine discolouration, brief nausea, a burning feeling if a little dye leaks at the injection site, or an itchy feeling. These are fairly common, estimated at up to around 1 in 10 people, and settle without treatment.
• Moderate reactions: an itchy rash or hives, which can be treated with antihistamines, fainting shortly after the injection, or a sore, swollen vein at the injection site. These need some treatment but aren't permanent.
• Severe reactions: very rarely, a serious allergic reaction, or other serious problems such as a stroke or heart attack.
• Death: extremely rare, estimated at less than 1 in 200,000 procedures.