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

The literature contains no reference to the effects in vivo of occlusion of the posterior ciliary artery (PCA) on the choroidal circulation. It has simply been assumed that occlusion of one or more PCAs is not likely to produce any filling defect in the choroid because the choroidal vascular bed has been described as being one continuous bed, with no segmental distribution (Nicholls, I938; Vilstrup, 1952; Wybar, I954a, b; Correia, I957; Scullica, 1957; Ruskell, 196I; Ring and Fujino, I967). Our experimental studies involving occlusion of the PCAs in rhesus monkeys have, on the contrary, revealed that such an assumption is entirely incorrect and that the distribution of the PCAs is, in fact, segmental. These studies have also led to many interesting observations which are reported below.