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FAG Investigation

Fluorescin angiography or imaging of the eye blood vessels with colouring agent

Fluorescin angiography (FAG) is a diagnostic procedure that maps the retina within a few minutes by taking a series of pictures of the eye and enables pathological processes to be detected, including pathological changes in blood vessels, haematomas, oedema and neoplasms.

During this procedure a colouring agent is injected into the patient’s vein in the arm that is delivered via the bloodstream into the blood vessels of the eye, and visualises possible diseases of the eye. Fluorescin is a bright yellow colouring agent that causes yellowish discoloration of the skin for a few hours. Since fluorescin is excreted via the kidneys, urine will also have a bright yellow colour for 24-36 hours after the investigation.

The following adverse effects have been reported after the use of this colouring agent: tiredness, nausea, vomiting, headache, stomach irritation, abstractedness, fainting, itching, and rash. On rare occasions life-threatening allergic reactions (anaphylactic shock) or breathing difficulties (caused by allergic reaction in the airways) have occurred. Very rarely leaking of the colouring agent into subcutaneous tissue has been observed when the venous cannula has moved away from its correct position or in case of a tear of the vein wall. In such a case it is recommended to wear a compressing bandage for a couple of days.

Intravenous fluorescin is usually not given to pregnant women or breast-feeding mothers, although there is no scientific proof that this could have a negative impact on an unborn baby or breast-fed infant.

Description of the procedure:

  • The procedure takes place at a pre-scheduled time. Please wear comfortable clothing enabling access to the veins on the arm.
  • There is no need to change the treatment regimen of other concomitant drugs (e.g. antihypertensive medicines).
  • Patients with diabetes are asked to eat before the investigation and administer insulin or oral antidiabetic drugs according to their treatment regimen.
  • The procedure lasts for approximately 1.5 hours (including preparation time).
  • Eye drops are instilled into the eye in order to widen the pupil.
  • Sensitivity to light of the eyes is increased and reading ability is impaired up to 24 hours after the procedure.
  • Venous cannula is inserted into the vein in the arm for administering colouring agent.
  • During the procedure the patient is sitting behind the apparatus making photographs of the eye and it is necessary to look at the direction indicated by the doctor.
  • After the administration of colouring agent you may be disturbed by the bright light that is directed into the eye in order to take pictures and perform the investigation.
  • Mild feeling of nausea is possible during the administration of colouring agent; it usually disappears within a few seconds.
  • Venous cannula will be removed after the procedure after it has been made sure that you feel good.
  • The doctor will provide you with a summary of the investigations and prepare a treatment plan, if necessary
  • It is not recommended to drive a car after the procedure (for up to 24 hours).