Walsh & Hoyt: Traumatic Optic Neuropathies: Injury Mechanisms

Optic nerve injury mechanisms are thought of as primary and secondary. Primary mechanisms result in permanent injury to the optic nerve axons at the moment of impact. Walsh felt that primary injury resulted in mechanical shearing of the optic nerve axon and vasculature. In contrast, secondary mechanisms cause damage to the optic nerve subsequent to the force of impact. He suggested that these mechanisms included ongoing vasospasm and swelling of the optic nerve within the confines of the nonexpansile optic canal leading to worsening ischemia and further loss of axons that possessed the potential for recovery immediately following impact