Indocyanine Green angiography (ICG)
ICG angiography is an investigation to study the Choroidal circulation integrity. In this investigation a dye called Indocyanine green is injected through the vein of an arm and the serial photographs of retina are taken alongwith time for 20 minutes. Indocyanine Green dye absorbs light of wavelength 750-805nm and emits light of wavelength 770-880nm. It is 98% protein bound and does not leak readily from blood vesels.
The indications of ICGA are
- Polypoidal Choroidal vasculopathy (PCV),
- Occult CNVM,
- Neovascularization associated with PED,
- Recurrant CNVM,
- Identifying feeder vessel in ARMD,
- Central serous Chorioretinopathy.
Other indications are:
- ICG guided laser treatment or photodynamic therapy of CNVM or Polypoidal Choroidal Vasculopathy.
- Dye is used for staining the ILM for peeling.
- Choroidal Tumors
Side Effects & Contra indications:
ICG angiography is a relatively safe procedure and it can be done in pregnant lady safely also. But it should be avoided in patients with Iodine allergy, hyperuricemia & impaired liver function.