Investigation of Blood Flow Velocity by Color Doppler Imaging in Nonischemic Central Retinal Vein Occlusion with Collateral Veins

Purpose: To study the blood flow velocity in the central retinal vein after the resolution of non-ischemic central retinal vein occlusion (CRVO) with optociliary vein (OCV). Methods: Eleven patients and 22 healthy volunteers were studied. Indocyanine green (ICG) angiography was used to investigate the choroidal veins in the affected eyes. Color Doppler imaging was used to measure the blood velocity in the central retinal artery and vein in the 11 affected and 22 healthy eyes. Results: Indocyanine green angiography verified the formation of retinochoroidal collaterals in all the affected eyes. The velocity in the central retinal vein was significantly lower in the affected eyes. Conclusions: The results indicate that the collaterals are important routes of extraretinal outflow of retinal venous blood. It is recommended in the investigation of CRVO by color Doppler imaging to perform ICG angiography to determine if retinochoroidal collateral veins have been formed.