Microvascular Architecture of the Retina in the Japanese Monkey (<i>Macaca fuscata fuscata</i>)

Abstract

The microvascular architecture of the optic region of the retina in the Japanese monkey was revealed under SEM utilizing microcorrosion casts by Ohta's method (1990). At the optic nerve disc, the central retinal artery radiated to four primary retinal arterioles. A dense retinal capillary network between these vessels extended outwards and showed regional differences in density. At the optic nerve disc part, the network developed into a multi-laminar structure containing the radial peripapillary capillaries at the innermost layer. At the macula, the retinal capillaries formed a ring around the central fovea (an avascular area). At the equatorial part, the network was observed to be double-layered: a superficial capillary network (on the vitreous side) located in the nerve fiber layer with a capillary-free zone (CFZ) 30-50μm in width around arterioles and a deep capillary network (on the choroid side) located at the external nuclear lamina without the CFZ. At the serrata ora, the network diminished to a single layer with coarse ovoid meshes, and the CFZ developed to 50-70μm in width around arterioles. In conclusion, the microvasculature of the retina in the Japanese monkey showed regional variations in proportion to the fine structures of the retinal layers. CFZ occurred since the retinal capillaries were located in the same level as the arterioles.