Occlusion of the posterior ciliary artery: I. Effects on choroidal circulation

Abstract

Choroidal circulation after occlusion of the lateral, medial, or all the posterior ciliary arteries (PCAs) was investigated in 85 rhesus monkey eyes by in vivo intravenous fluorescence angiography and in thirty of these by post mortem silicone rubber perfusion of the vascular bed. The segmental distribution of the PCAs is stressed. In lateral and medial PCA occlusions, the filling of the choroid supplied by the occluded artery, immediately after the occlusion, was delayed till after the retinal venous phase, when sluggish, incomplete filling took place via collaterals from the posterior episcleral arterial plexus and by retrograde circulation through the vortex vein tributaries, but not from the normally filling choroid. One to two days later, the filling appeared earlier and was more extensive. Progressive improvement in filling took place until, at 2 to 3 weeks after the occlusion, the choroid filled in the affected area, although delayed. In occlusion of all PCAs, centrifugal arterial filling from the peripapillary choroid extended into the affected area of choroid, incompletely and sluggishly at first, but completely, though delayed, 3 to 4 weeks later. The filling was thought to take place via the pial plexus of the optic nerve and the posterior episcleral arterial plexus.