[Vascularization of the iris].

A part of the LEBER's scheme concerning vascularization of the iris may be discussed from iridian angiograms. Serial frontal sections permit to precise the following data: The great arterial circle, which is in a tight relation with the ciliary muscle gives rise to one artery by ciliary process, and veins are located more posteriorly. The iridian zone proper has one radiate artery for 3 or 4 veins. The small arterial circle located in the collarette zone is variable, most often discontinuous. The iridian sphincter zone has a high density vascularization, constituted of antero-posterior vessels, realizing a pre-sphincterian and retro-sphincterian networks. The marginal circle always exists; it seems mostly of an arteriovenous type. The density of this vascularization exceeds the nutritional needs of this organ, and suggests an other functional role.