Occlusion of the posterior ciliary artery. V. Protective influence of simultaneous vortex vein occlusion.

In 28 eyes of rhesus monkeys, occlusion of all the posterior ciliary arteries (PCAs) was either performed alone (in seven eyes) or accompanied simultaneously by occlusion of one vortex vein (VV) (in 11 eyes) or two VVs (in ten eyes). In addition, in four eyes lateral PCA occlusion was combined with occlusion of two VVs. All the eyes were investigated for acute ischemic lesions in the fundus, ie, outer retinal infarcts and anterior ischemic optic neuropathy (AION). The findings indicate that occlusion of one or two VVs exercised a distinct protective influence against the acute ischemic lesions. The study also demonstrated that notable interstudy and intrastudy variations in the incidence and extent of retinal infarcts and AION among the various previously reported experimental PCA occlusion studies were caused by unintentional and unnoticed cutting of some of the VVs in the orbit.