The presence and distribution of centrifugal fibers in the human retina has been studied using retinal fiat mounts and silver impregnation techniques. The method has permitted identification of individual centrifugal fibers which emerge from the optic papilla as well as their course and distribution within the retina. These centrifugal fibers can be differentiated from axons of ganglion cells by their diameter, by their intense argyrophilia, by their successive bifurcations as they proceed peripherally in the retina resulting in attenuation of the fibers, and by their descending trajectory from the nerve fiber layer into the inner nuclear layer. Parallel studies of vertical retinal sections have confirmed with more precision the descending trajectory of the centrifugal fibers from the nerve fiber layer across the ganglion cell and inner plexiform layer to reach the innermost portion of the inner nuclear layer where the majority of the fibers terminate. However, occasional fibers cross the inner nuclear layer to end in the outer plexiform layer.
Honrubia FM, Elliott JH. Efferent Innervation of the RetinaI. Morphologic Study of the Human Retina. Arch Ophthalmol. 1968;80(1):98–103. doi:10.1001/archopht.1968.00980050100017