Occlusion of the vortex veins: An experimental study

Abstract

In forty eyes of rhesus monkeys, the various vortex veins (VVs) were cauterized outside the globe close to their exit in various combinations, i.e. one, two, three, or all the VVs. Eighteen eyes were followed for periods of up to 3 months. The occlusion produced immediate venous congestion and stasis in the segment of the uveal tract drained by the occluded vein. The vessels in the ciliary processes were most affected by the occlusion which resulted in the production of protein-rich aqueous and, on occlusion of two, three, or all VVs, additional haemorrhages were seen, resulting in hyphaemata-the more VVs were occluded, the morefrequent were the hyphaemata. In cases with occlusion of three or all VVs forward movement of the iris-lens diaphragm was associated with raised intraocular pressure and a shallow or absent anterior chamber; these eyes later developed degenerative changes, e.g. iris atrophy with anterior and posterior synechiae, cataractous lens, vascularized cornea, and atrophy of the ciliary processes with ocular hypotony. On follow-up, normal uveal circulation was re-established after i or 2 weeks or longer, depending upon the number of VVs occluded. Clinically, VV occlusion can mimic non-granulomatous anterior uveitis and some of these cases resemble the syndrome of anterior segment ischaemia. The pathogenesis of some of the major complications of retinal detachment surgery is discussed in the light of the findings.