Shunt Vessel Meningioma

RETINO-CHOROIDAL (OPTO-CILIARY) COLLATERAL VESSELS: (also known as Retinal-choroidal venous collaterals, opticociliary veins or ciliary shunt vessels) Retino-choroidal collaterals are potential telangiectatic connections between the retina and choroidal circulation. Although sometimes called "shunts", these collaterals are between the retinal venous circulation and the choroidal venous circulation. These collaterals are present congenitally but not normally open unless there is obstruction to venous blood flow, in which case these collateral veins open and become large and engorged. They close when the obstruction is removed.