Ultrastructural study on centrifugal fibers in the feline retina

Morphological studies were carried out to elucidate whether centrifugal fibers are present in the cat retina. Unilateral optic nerve transection with the minimum vascular damage was performed at 6 mm behind the eyeball via the soft palate approach in adult specific pathogen free cats. Light and electron microscopic observations were performed at 40 and 96 hours after the optic nerve transection. At 40 hours, when there was no evidence of degenerative change in the retinal ganglion cells, degenerative changes were observed in the neuronal processes in the outer part of the inner plexiform layer. Two forms of degeneration occurred in close proximity to the cell bodies or the processes of amacrine cells: electron opaque and electron lucent degeneration. Since degeneration of the ganglion cells became manifest at 96 hours, the early neuronal changes in the inner plexiform layer were thought to represent degeneration of the centrifugal fibers.