Purchase this article with an account.
Alireza Karimi, Reza Razaghi, Christopher A Girkin, J Crawford C Downs; Ocular biomechanics during improvised explosive device blast. Invest. Ophthalmol. Vis. Sci. 2021;62(8):684.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Eye injuries are found in 10-13% of all combat casualties and, more recently, among civilians with improvised explosive device (IED) injury. Bomb blast injuries exerts a shearing force on the air-tissue interfaces through the blast wave, invoking a significant acute IOP elevation. A sudden elevation in the IOP could significantly amplify the mechanical deformation and/or strain within the laminar region that result in neuronal cell death. This study is aimed to estimate the stresses and deformations in the ONH due to IED explosion using a set of two eye-specific fluid-structure interaction (FSI) ONH models.
Eye-specific FE models of the ONH, including the pia, optic nerve, LC, sclera, and retina were constructed based on the 3D delineation of anatomic surfaces of the posterior eye obtained from two human donors and then the generic anterior segment was added. An IED with the weights of 1 and 2 kg was placed within 2, 3, and 4 m of the victim’s temporal (side) and frontal (front) while the ground was covered with a deformable soil to reflect the blast wave. Prior studies ignored the overpressure due to the blast reinforcement by the ground.
Reflection of the bomb blast pressure from the ground reached to the eye prior to the bomb blast pressure itself, which suggests a crucial role for the ground in reinforcement of the blast pressure and ocular injury simulations. Results revealed an IOP elevation of ~ 6,000-48,000 mmHg, with the highest IOP for the IED weight of 2 kg/victim distance of 2 m (front blast) and the lowest for the IED weight of 1 kg/victim distance of 4m (side blast); this suggests the important role of the victim’s position with respect to the blast wave in ocular injury analyses (Figure). IOP was elevated by ~2900 and ~2700 mmHg within 1.6 ms after the blast for the front and side blasts, respectively, matching values reported in the literature, but IOPs were much higher due to ground blast reinforcement after 1.6 ms. Stresses and strains were highest in the temporal quadrant of the eye.
The findings of this study have implications for not only understanding of the stresses and deformations in the ONH due to IED explosion, but also for providing information for the military experts to design a better visor (eye armor) to help break the stress of the wave pressure and protect against blast-induced injuries in the ocular-orbital region.
This is a 2021 ARVO Annual Meeting abstract.
This PDF is available to Subscribers Only