[Holographic deformation analysis of the optic canal in blunt cranial trauma]

The problem in question is the uni- and ipsilateral, acute and irreversible blindness following a minor blunt trauma to the skull without any evidence of a fundus pathology, a fracture in the optic canal or a nerve sheath hematoma. Human cadaver skull bases were examined under static load by means of holographic interferometry. It could be shown that stress lines run in a longitudinal and sagittal direction through the ipsilateral, but transversely through the contralateral optic canal. The complex arrangement of the collagen fibers in the optic nerve sheath and its tough fixation to the bony canal allow only longitudinal-sagittal stress forces to be conducted to the nerve itself, which is consequently stretched and compressed. The transverse direction of the stress lines in the contralateral optic canal, however, are without any mechanical influence on the nerve.