Frequently
Asked Questions
Use of Indocyanine Green for Injection,USP
in Ophthalmology
Frequently Asked Questions
We’ve put together some commonly asked questions about Diagnostic Green’s Indocyanine Green for Injection, USP (ICG),
in the use for Ophthalmics.
If you can’t find the answer to your question, please contact us
Indocyanine Green Injection for USP, known as Verdye in a number of European territories (ICG) is a tricarbocyanine dye with both hydrophilic and lipophilic properties. The retention of ICG in the fenestrated choroidal circulation, combined with its low permeability, makes ICG angiography ideal for viewing the choroidal blood vessels. Once injected, ICG binds to plasma proteins and quickly circulates to the choroid layer, delineating the choroidal veins within 15-20 secs.
ICG is cleared exclusively through the liver and then excreted through the bile. It does not undergo metabolism. It has an excellent safety profile and adverse reactions occur very rarely (<1/10,000).
ICG for Ophthalmic Retinal Angiogram was introduced in 1973. Since then, ICG for ophthalmic retinal angiogram can be used to investigate Retinal disorders including Macular/Choroidal/Outer Retinal Disorders.
Indocyanine Green Angiography (ICGA) is the gold standard in diagnosing a number of serious eye conditions and is a key diagnostic tool used by ophthalmology specialists worldwide.
ICGA is particularly useful in the differential diagnosis of
- Polypoidal Choroidal Vasculopathy (PCV)
- Central Serous Chorioretinopathy (CSCR)
- Retinal Angiomatous Proliferation (RAP), which can be misdiagnosed as nAMD (Neovascular Age-related Macular Degeneration)
- Investigation of complex posterior uveitis and white dot syndromes
- Assessment of patients with “wet” AMD where the presence of polypoidal choroidal vasculopathy (PCV) is in question
- The assessment of choroidal hyperpermeability in patients with central serous chorioretinopathy.
Videoangiogram recordings via Scanning Laser Ophthalmoscopy allow for rapid identification of high contrast images.
(Neovascular Choroidal Membranes).
25mg/10ml Sterile Water dilution. 5ml bolus intravenous injection.
Early Phase: 60 Seconds – Choroidal Leakage/Irregular Choroidal Capillaries / Choroidal filling defect
Mid Phase: 1-3 Minutes
Late Phase: 15-45 Minutes – Hyper/Hypo Fluorescent spots – Cannot be detected with other Fluorescein angiography.
Product Information Leaflet Indocyanine Green for Injection, USP Package Insert.
Applications where ICGA is considered superior include
- Polypoidal Choroidal Vasculopathy (PCV) ICG superior to Fluorescein Angiography (FA)
- Chronic Central Serous Chorioretinopathy (CSCR) ICGA preferred method for high quality images of leakage and dilated choroidal vessels
- Posterior Uveitis – ICGA provides more information than FA. Behcets’ Uveitis/Chorioretinopathy/Posterior Scleritis
- Choroidal Tumors Identification via vascular patterns
There are a number of reasons including:
- ICG’s unique pharmacokinetics, which allows for a choroidal vasculature image that is better than that using FA
- Studies have indicated up to 77% greater visualization of hypo/hyperfluorescent lesions observed with ICGA over FA
- ICGA -Important role in management of macular disorders with subclinical neovascular lesions, exudative process harbor plaques of neovascularization evident with ICGA, not FA
- ICG-guided feeder vessel photocoagulation: SLO high speed ICGA images 0.5-3mm length feeding vessels of the CNVM.
FA images Retinal Circulation whereas ICG images Choroidal circulation. These occur at different layers of the Retina.
FA is a low molecular weight molecule, and binds at an 80% level to plasma protein. ICG on the other hand has high molecular weight and binds to protein at 98%.
Light Emission: FA: Visible Spectrum, ICG: Infrared Spectrum.
FA – Observed via Blue/Green Filter, ICG: Infrared Filter
Technology for Retinal Imaging has continued to develop, including Ocular Coherence Technology (OCT).
Advantages and disadvantages in comparison to ICGA.
ICGA | OCTA |
ICGA fluorescence can penetrate blood, fluid and retinal pigment epithelium to reveal underlying abnormalities of the inner choroidal vasculature and is essential for making a definitive diagnosis of PCV. | Extremely motion sensitive, requiring a patient to fixate on precise point for several seconds. Patient compliance required, which is often difficult, particularly for older patients. |
Excellent visualization within minutes, of the medium & large choroidal vessels. | OCTA takes more time than structural scans and requires trade-offs in flow resolution, scan quality and speed. |
ICGA is beneficial in the differential diagnosis of PCV, Chronic CSC, and RAP. | Limited field of view leading to a greater likelihood that lesions may be missed. |
ICGA has been shown to optimize detection of capillary macro aneurysms in longstanding diabetic macular edema (DME) or retinal vein occlusion (RVO). | Failure to recognize OCTA Projection Artifact (blood vessels seem at erroneous location), may lead to inaccurate clinical assessment. |
A recent study demonstrated that late leakage in ICGA occurred in all RAP cases | Image processing for OCTA can alter blood vessel appearance through segmentation defects, and image display software can lead to false impressions of vessel location and density |
Duration of ICGA procedure only 15-20mins, very quick analysis. | The analysis of these images is time-consuming – may involve many hours of post hoc manual segmentation work, which may be difficult to accommodate during daily medical work routines. |
To report suspected adverse reactions:
contact us at 1-844-424-3784 or e-mail drugsafety@diagnosticgreen.com