Effects of intracameral Na2EDTA and EGTA on aqueous outflow routes in the monkey eye.

Intracameral perfusion with 4 to 6 mM Na2EDTA or 4 mM EGTA for 40 to 80 min caused a very large increase in gross outflow facility. This effect was partly reversible when followed by perfusion with mock aqueous humor. Eyes perfused with Na2EDTA were studied morphologically. In the trabecular meshwork the cells separated due to a splitting of the cell junctions. A distention of the cribriform meshwork, a wash-out of extracellular material , and a disintegration of the denuded trabecular cores were also noticed. The inner wall of Schlemm's canal protruded in a "balloonlike" manner into the lumen of the canal and showed frank ruptures, especially after prolonged perfusion times. The conventional outflow pathways beyond Schlemm's canal showed no abnormalities. In the uveoscleral outflow routes the anterior and middle part of the ciliary muscle demonstrated very wide intermuscular clefts and many degenerated muscle fibers. The posterior third of the muscle was normal. So were the ciliary epithelium, the choroid, and the retina. The pupillary sphincter also showed degeneration. The corneal endothelial cells separated, starting at the apical junctional complex.