Indocyanine green angiography (ICGA) is a diagnostic procedure used to examine choroidal blood flow and associated pathology.

[1][2] The near infrared light used in ICGA penetrates ocular pigments such as melanin and xanthophyll, as well as exudates and thin layers of sub-retinal vessels.

[4] Indocyanine green angiography is widely used to study choroidal neovascularization in patients with exudative age-related macular degeneration.

Because of its protein-binding properties, its leakage from choriocapillaries is less and thus it will remain longer in choroidal vessels compared to fluorescein dye.

In 1968, Kogure et al. performed intra-arterial choroidal absorption angiography using indocyanine green dye in monkeys.