ICG-enhanced digital angiography and photocoagulation of choroidal neovascularization in age-related macular degeneration

ABSTRACT

Choroidal neovascular membranes are often poorly defined on fluorescein angiography because of fluorescein leakage or blockage of hyperfluorescence by overlying hemorrhage, lipid, turbid fluid, or pigment. Indocyanine green (ICG) is a highly protein-bound dye in the near infrared portion of the spectrum. Therefore, ICG remained in and around the neovascular membrane and enhanced the visualization of certain membranes poorly defined with fluorescein. ICG penetrated through the overlying turbid tissue, and improved the visualization of the underlying choroidal neovascular membrane. Using an infrared angiography system, the authors obtained 21 ICG-angiograms with suspected choroidal neovascularization, and compared them to fluorescein angiograms. In 5 of the 21 eyes, occult choroidal neovascularization was well delineated on the ICG angiograms. In 2 eyes, we were able to detect a well-defined choroidal neovascular membrane underlying a subretinal hemorrhage. In 12 of the 21 eyes with choroidal neovascular membrane, we performed argon-green laser photocoagulation applying the overlay technique of the ICG angiogram to red-free photo or the early fluorescein angiogram, and evaluated the effect of full coverage laser treatment.