We used a pars plana approach to experimentally induce retinal vein occlusions (RVO) in cats by the application of electric energy near the veins at the optic nerve head. This experimental model was utilized to study the natural evolution of thrombosis in the cilioretinal veins, which are located near the lamina cribrosa in the cat. We observed that occlusion of the retinal veins occurs by the formation of a thrombus and that with time there is associated endothelial cell proliferation and recanalization in each instance.