Posterior Ciliary Artery Occlusion and Choroidal Ischemia

Abstract

The posterior ciliary arteries (PCAs) supply the choroid and the optic nerve head. As discussed in Chap. 4, information on the vascular pattern of the choroid and of the PCAs was previously drawn entirely from postmortem cast studies, ever since the first description by Frederik Ruysch [1] in 1700. Extensive anatomical studies of the choroidal vascular bed have been conducted, mostly by studying casts prepared by the postmortem injection of a variety of materials [2–8] and also by studying casts by scanning electron microscopy [9–12]. These studies formed the basis of the classical anatomical textbook description of the choroidal vasculature. According to most of these descriptions: (1) PCAs have no segmental distribution, (2) they anastomose freely with one another as well as with the anterior ciliary arteries, (3) there are inter-arterial and arteriovenous anastomoses in the choroid, and (4) the choriocapillaris forms a freely communicating and an uninterrupted vascular bed in the entire choroid [8, 11]. From these postmortem anatomical descriptions, it was generally concluded that occlusion of PCA or one of its branches should not produce an ischemic lesion.