Centrifugal nerve fibers in the adult human optic nerve: 16 days after enucleation.

The optic nerve stump of a 56-year-old patient was removed 16 days after enucleation of the corresponding eyeball. The stumps of numerous centrifugal (efferent) nerve fibers are demonstrated histologically in this optic nerve central to the 16-day old surgical cut. Electron-microscopic views of the centrifugal nerve fibers are offered for the first time. The findings are further evidence for the existence of centrifugal fibers in the human optic nerve. The nerve fiber stumps exhibit reactive terminal swellings pointing towards the surgical cut indicating axoplasmic flow in that direction. It is of special interest that the centrifugal nerve fibers of this 56-year-old patient lack any evidence of attempted regeneration that has been observed under similar conditions in th optic nerve stump of a child.