Purchase this article with an account.
Walter Gray, Richard Watson, Matthew Reilly, Brian Lund, Rick Sponsel, Randolph Glickman; A Computational Model for Investigation of Ocular Trauma Due to Primary Blast. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3045.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Ocular trauma due to blast has increased dramatically in the Iraq and Afghanistan conflicts. Eye trauma has been observed in approximately one-quarter of battlefield injuries. However, trauma from blast pressure alone, or primary blast, is not well documented as pressure is commonly accompanied by debris and acceleration of the body. Some researchers argue that primary blast cannot create significant ocular trauma, instead serious injury results from the secondary debris or body acceleration. Recent experiments have suggested the potential for injury from high levels of blast pressure. To further evaluate this hypothesis and investigate the experimental results, high-fidelity computational models of the eye were developed and exercised. Modeling confirmed the reality of primary blast injury and allowed for identification of the physical mechanisms responsible.
Numerical simulations were run in conjunction with shock tube experiments. Sub-lethal blast levels (7-22 psi; 2 ms) were used in the experiments and modeling. Previous experiments focused on globe rupture, but our interest was characterizing lower but potentially serious internal injuries. Two different numerical models were used: (1) a Lagrangian Finite Element Analysis (FEA) model with fluid/structure interaction, and (2) a Eulerian finite volume hydrocode. High-fidelity geometrical and tissue constitutive representations were developed and implemented in both models.
The computational models successfully predicted the types of injury observed in the physical experiments. Observed injuries included retinal detachment, angle recession, lens displacement, and injury to the iris and zonules. Higher levels of blast pressure were associated with higher levels of injury. However, some injury types could not be duplicated with the models. Specifically smearing of pigment into the optic nerve was observed in the experiments, but could not be duplicated with the current models.
The numerical models confirmed the potential for ocular injury due to primary blast. Computational results were well correlated with the physical experiments and provided invaluable insight into the mechanisms responsible for injury. The models can therefore be used in future efforts to evaluate protection schemes against primary blast.
This PDF is available to Subscribers Only