Real-Time Laser Light Simulation of Orbital Bone Reflection and Focusing of Blast Wave Energy

Shock wave overpressure associated with primary blast events are believed to induce ocular trauma and loss of vision under the right conditions. In reality, clinical case studies involving ocular blast exposure are difficult to correlate to combat conditions such as blast direction. Wide variations in reported trauma suggest that there is an underlying complexity associated with head anatomy. However, the complex nature of the orbital topography makes it difficult to know precisely whether this assumption holds true. Use of light allows a real-time assessment of where the total amount of light entering the orbit comes to a focus with respect to the location of the optic nerve and retina. Differences in focus due to changes in the incident wavefront direction were tested. Also, isolated entry points into the orbit were examined separately. Photography was used to record variations of focusing on the surface of a simulated optic nerve placed within the orbit. Results indicate differences in focus location with changes in wavefront orientation, with some focus points located deep in the orbit, or only on one side of the nerve. In some instances, pinch-point like focusing was seen from different directions along the nerve. The use of the model gives better insight into how shock wave energy may be focused within the orbit.