Fluorescein angiography is an imaging procedure. It is used to diagnose diseases of the fundus of the eye. A suitable dye (e.g. self-luminous fluorescein or indocyanine green) is injected into the bloodstream as a contrast agent. This makes the blood vessels in the eyes more visible.
Here you will find further information and selected fluorescein angiography specialists and centers.
Angiography is a diagnostic imaging procedure used to visualize blood vessels. It is painless and low-risk. Fluorescein angiography is a special form that is used in ophthalmology.
The procedure is based on X-ray or MRI images. As a rule, a contrast agent is injected into the vessels for better visualization.
Fluorescein angiography is often used for eye diagnosis. Unclear changes in the retina and choroid can thus be better clarified.
In particular, the doctor examines the extent of diabetic changes to the retina. This procedure is also used
The retina during fluorescein angiography © L. Bacud | Wikimedia Commons
Fluorescein angiography is particularly suitable for eye diseases with causes in the area of the eye vessels. These include
Diabetic retinopathy is a disease of the retina caused by diabetes mellitus. Diabetes also damages the small blood vessels in the eye. This leads to unnoticed damage to the retina.
In the further course of the disease, blindness can occur under certain circumstances.
Treatment can delay the progression of the disease and, in the best case, stop it. As a preventive measure, diabetes mellitus should be optimally controlled.
Anterior ischemic optic neuropathy (AION) is an acute occlusion of an ophthalmic artery in the Zinn-Haller vascular cortex, which supplies the optic nerve. This initially leads to insufficient blood flow to the optic nerve head. As a result, the optic nerve is insufficiently supplied with oxygen and nutrients.
AION is an emergency situation and is also known colloquially as an eye infarction.
Age-related macular degeneration (AMD for short) is a loss of central visual acuity. The disease occurs at an advanced age and continues to progress.
Although visual acuity decreases significantly, blindness is not to be expected even in the late stages. The loss of vision only affects the so-called macula (central part of the retina of the eye). The rest of the retina remains unaffected by the disease. Visual performance in the outer field of vision is not affected.
Orientation in the environment is therefore usually possible without difficulty despite AMD.
However, those affected can only perceive light-dark contrasts. This usually means a loss of reading ability and the ability to drive. Those affected can also only recognize other people with difficulty.
Before carrying out the scan, the doctor needs information about the patient's general condition, such as
The patient should provide the doctor with a list of any medication to be taken.
Before the actual fluorescein angiography begins, the doctor administers eye drops to the patient. These dilate the pupils. The dilated pupils allow the doctor to take photos of the retina when the eye is at rest. He then photographs the eye under special lighting conditions. This results in a better contrast between the retina and the blood vessels.
The patient is then injected with a fluorescent dye into the arm vein. Two dyes are available:
Fluorescein angiography works slightly differently depending on the dye. The dye spreads well in the body, but especially in the eyes.
The eye is then irradiated with short-wave blue light. Further images of the eyes are taken at regular intervals. This allows the distribution of the dye in the eye to be observed. This enables the doctor to assess whether there are any constrictions in the eye or whether the blood vessels are healthy.
Especially in patients with
this is of particular importance. Diseases of the retina or blood vessels can also be diagnosed with the help of fluorescein angiography.
The dye fluorescein is injected into the body via an access port in the arm or hand vein. The dye is distributed throughout the body and appears in the eye vessels after just a few seconds.
During the examination, the patient sits behind a special camera or a laser scanning system. These systems digitally record the flow of the dye into the vessels of the eye and other layers of the retina.
The dye causes the skin to turn a slightly yellowish color after the examination. After 4 to 6 hours, this appearance disappears again and the dye is excreted in the urine.
Fluorescein belongs to the group of xanthene dyes. Fluorescein is used as an indicator in analytical chemistry.
In addition to its use as a colorant in ophthalmology, fluorescein has a wide range of applications. For example, it is used as a colorant for soaps and bath extracts. Fluorescein is also used in flow cytometry and fluorescence microscopy. Among other things, it can be used to detect pathogens in
or tissues. Fluorescein has a so-called high quantum yield of up to 93 percent.
However, the dye also has disadvantages. The intensity of the dye depends on the pH value. If this falls below a value of 7, the intensity decreases. In addition, the fluorescence decreases very quickly under illumination and the fluorescence maximum is not sufficiently sharp.
Fluorescein is available in two different structures:
Indocyanine green angiography is performed in the same way as fluorescein angiography. Indocyanine green (ICG for short) primarily shows the choroidal vessels and structures. This procedure therefore enables a deeper visualization of the layers of the retina.
Angiography with the dye indocyanine green requires specially designed laser scanning systems. It is therefore very complex in terms of equipment.
The dye is broken down by the liver and excreted through the bile ducts. Indocyanine green is an iodine-containing, well-tolerated dye. For this reason, there should be no intolerance to iodine.
In case of
indocyanine green angiography should not be performed.
If the thyroid gland is hyperactive, treatment should only be carried out after consultation with the attending physician.
The dye indocyanine green (ICG for short) is also a fluorescent dye. It is primarily used in medicine as an indicator and has a half-life of around 3 to 4 minutes. It is then eliminated from the body after intravenous administration and depending on the performance of the liver.
The so-called ICG sodium salt is available in powder form. This allows it to be used in a wide variety of solvents. In order to achieve better solubility, sodium iodide is added to the powder.
As a rule, fluorescein angiography is painless and without complications for the patient. In most cases, a yellowing of the skin and urine occurs for about one to two days after the procedure. This condition can last up to 24 hours and the dye is excreted via the kidneys.
The pupil is dilated during fluorescein angiography. Patients may therefore experience other side effects during and after the examination:
As a rule, allergic reactions to the fluorescein or indocyanine green dyes are rare. However, if this does happen
may occur. In these cases, depending on the severity of the symptoms, the patient is given
Nausea, vomiting and dizziness may also occur in rare cases after the examination. However, these side effects are only of short duration.
Only very rarely have the injection at the injection site caused
observed.
The examination is usually followed by an evaluation and discussion of the findings. This allows a further treatment plan to be drawn up together with the ophthalmologist.
As a general rule, the patient must not drive for several hours after the examination due to the dilation of the pupils.
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