SCANNING ELECTRON-MICROSCOPIC STUDY OF EPISCLERAL ARTERIOVENOUS ANASTOMOSES IN THE OWL AND CYNOMOLGUS MONKEY

In the present study we have analyzed the architecture of the episcler al microvasculature in the owl and cynomolgus monkey using scanning el ectron microscopy of resin casts. Due to the topical pretreatment with nitroprusside the complete vasculature including segments of the aque ous humor outflow channels could be visualized. We found that 1-3 mm p osterior to the limbus corneae the episcleral vessels form numerous ar teriovenous anastomoses (AVA) in the size of small arterioles and venu les. These AVA are also located at the collector channels near Schlemm 's canal and at the episcleral venous plexus which drains the collecto r channels. It is assumed that the AVA might influence not only the ci rculation in the episcleral venous plexus but also in the aqueous humo r outflow routes.