The retinal capillary bed at the posterior pole of primate eyes

The capillary circulation in the posterior pole was studied by fluorescein angiography and silicone rubber injection in eight species of primates. Six of these were diurnal monkeys: marmoset, squirrel moneky, capuchin monkey, black spider monkey, African green monkey, and rhesus monkey. In these diurnal species, the retinas have both rods and cones, and there is a central region free of capillaries that corresponds to the fovea, just as in the human retina. In two nocturnal species, the bushbaby and the owl monkey, both of which lack a fovea, there is no central capillary-free zone.