Indirect traumatic optic neuropathy induced by primary blast: a fluid-structure interaction study.

Current knowledge of traumatic ocular injury is still limited as most studies have focused on the ocular injuries that happened at the anterior part of the eye, whereas the damage to the optic nerve known as traumatic optic neuropathy is poorly understood. The goal of this study is to understand the mechanism of the traumatic optic neuropathy following the primary blast through a fluid-structure interaction model. A 3D eye model with detailed orbital components was developed to capture the dynamics of the eye under the blast wave. Our numerical results demonstrated a transient pressure elevation in both vitreous and cerebrospinal fluid. A high strain rate over 100 s-1 was observed throughout the optic nerve during the blast with the most vulnerable part located at the intracanalicular region. The optic nerve deformed at such a high strain rate may account for the axonal damage and vision loss in patients subjected to the primary blast. Results from this work would enhance the understanding of indirect traumatic optic neuropathy and provide guidance in the design of protective eyewear against such injury.