We examined an eye with melanomalytic glaucoma by quantitative aqueous perfusion, light and electron microscopy. Facility of outflow was markedly diminished from normal in vivo and in vitro. The trabecular meshwork was heavily laden on its surface and in the intertrabecular spaces with macrophages. Many of these cells appeared to be wandering macrophages, while some appeared to be detached, phagocytic trabecular endothelial cells.