Retinal Sequelae of Primary Ocular Blast Injuries

Chalioulias, Konstantinos; Sim, KT; Scott, Robert A H

doi:10.1136/jramc-153-02-11

Cited by 33 publications

(16 citation statements)

References 3 publications

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“…Zuckerman 26 reported retrobulbar hemorrhage after PBI, and Shelah et al 27 described a dog who suffered blindness after blast exposure. Chalioulias et al 6 also reported mydriasis in a soldier who was leaning his head on the metallic door pillar of an armored vehicle hit by an explosion.…”

Section: Discussionmentioning

confidence: 99%

“…Initially described exclusively in hollow, air-filled organs, 1,2 the spectrum of PBI progressively enlarged to encompass fluid-filled organs, including the central nervous system 3,4 and the eye. [3][4][5][6] Macular holes, choroidal rupture, and optic nerve damage occur relatively frequently after blunt trauma, 7 and although the pathogenic mechanism remains unclear, vitreous traction, 8 globe deformation, differential eye layer stiffness, 9 shockwave propagation, and multiaxial strain 10 likely participate.…”

Section: Resultsmentioning

confidence: 99%

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Primary Blast Injury to the Eye and Orbit: Finite Element Modeling

Rossi¹,

Boccassini

Esposito

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. Primary blast injury (PBI) mostly affects air-filled organs, although it is sporadically reported in fluid-filled organs, including the eye. The purpose of the present paper is to explain orbit blast injury mechanisms through finite element modeling (FEM).METHODS. FEM meshes of the eye, orbit, and skull were generated. Pressure, strain, and strain rates were calculated at the cornea, vitreous base, equator, macula, and orbit apex for pressures known to cause tympanic rupture, lung damage, and 50% chance of mortality. RESULTS.Pressures within the orbit ranged between þ0.25 and À1.4 MegaPascal (MPa) for tympanic rupture, þ3 and À1 MPa for lung damage, and þ20 and À6 MPa for 50% mortality. Higher trinitrotoluene (TNT) quantity and closer explosion caused significantly higher pressures, and the impact angle significantly influenced pressure at all locations. Pressure waves reflected and amplified to create steady waves resonating within the orbit. Strain reached 20% along multiple axes, and strain rates exceeded 30,000 s À1 at all locations even for the smallest amount of TNT.CONCLUSIONS. The orbit's pyramidlike shape with bony walls and the mechanical impedance mismatch between fluidlike content and anterior air-tissue interface determine pressure wave reflection and amplification. The resulting steady wave resonates within the orbit and can explain both macular holes and optic nerve damage after ocular PBI. (Invest Ophthalmol Vis Sci. 2012;53:8057-8066) DOI:10.1167/iovs.12-10591 P rimary blast injury (PBI) refers to biological damage caused by the peak incident overpressure (PIO) wave generated by an explosion. Initially described exclusively in hollow, air-filled organs, 1,2 the spectrum of PBI progressively enlarged to encompass fluid-filled organs, including the central nervous system 3,4 and the eye. 3-6Macular holes, choroidal rupture, and optic nerve damage occur relatively frequently after blunt trauma, 7 and although the pathogenic mechanism remains unclear, vitreous traction, 8 globe deformation, differential eye layer stiffness, 9 shockwave propagation, and multiaxial strain 10 likely participate.Finite element modeling (FEM) is a numerical analysis method largely used to simulate multiphysics problems. Previous applications to ophthalmology [11][12][13] and, specifically, to blunt eye trauma 10 have been reported. The purpose of the present paper is to create a computational model of ocular PBI, simulate the propagation of blast waves through the orbit, and explain its pathogenesis. The study was prompted by the observation of macular holes, multiple choroidal ruptures, subretinal bleeding, and optic atrophy after blast exposure, in the absence of any contact with splinters and/or flying objects (Fig. 1). MATERIALS AND METHODS Finite Element ModelingThe eye model has been previously described, 10,14 while orbit and retrobulbar fat tissue were reconstructed based on patient computed tomography scan and magnetic resonance imaging ( Fig. 2; see the Appendix for further technical details on FEM). C...

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Section: Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Primary Blast Injury to the Eye and Orbit: Finite Element Modeling

Rossi¹,

Boccassini

Esposito

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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show abstract

“…Within the eye, blast trauma can cause injuries such as hyphema, retinal detachment, retinal edema, traumatic optic neuropathy, and loss of visual field 9, 11, 13, 32. Another mouse model of closed‐globe blast trauma directly applied to the eye saw a similarly delayed decrease in visual acuity, potentially due to the gradual increase in oxidative stress, neuroinflammation, and focal cell death 33.…”

Section: Discussionmentioning

confidence: 99%

Acute vitreoretinal trauma and inflammation after traumatic brain injury in mice

Evans

Newell

Mahajan

et al. 2018

Ann Clin Transl Neurol

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ObjectiveLimited attention has been given to ocular injuries associated with traumatic brain injury (TBI). The retina is an extension of the central nervous system and evaluation of ocular damage may offer a less‐invasive approach to gauge TBI severity and response to treatment. We aim to characterize acute changes in the mouse eye after exposure to two different models of TBI to assess the utility of eye damage as a surrogate to brain injury.MethodsA model of blast TBI (bTBI) using a shock tube was compared to a lateral fluid percussion injury model (LFPI) using fluid pressure applied directly to the brain. Whole eyes were collected from mice 3 days post LFPI and 24 days post bTBI and were evaluated histologically using a hematoxylin and eosin stain.Results bTBI mice showed evidence of vitreous detachment in the posterior chamber in addition to vitreous hemorrhage with inflammatory cells. Subretinal hemorrhage, photoreceptor degeneration, and decreased cellularity in the retinal ganglion cell layer was also seen in bTBI mice. In contrast, eyes of LFPI mice showed evidence of anterior uveitis and subcapsular cataracts.InterpretationWe demonstrated that variations in the type of TBI can result in drastically different phenotypic changes within the eye. As such, molecular and phenotypic changes in the eye following TBI may provide valuable information regarding the mechanism, severity, and ongoing pathophysiology of brain injury. Because vitreous samples are easily obtained, molecular changes within the eye could be utilized as biomarkers of TBI in human patients.

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“…Primary ocular is the result of direct impact by blast overpressure. It is still inconclusive whether blast pressure on the eye will lead to serious ocular injuries (Abbotts et al 2007;Chalioulias et al 2007). Due to mixed explosion conditions and unreliable diagnosis, experimental analysis could not be a feasible method to differentiate which type of ocular injury is caused by a specific blast effect.…”

Section: Introductionmentioning

confidence: 99%

Prediction of globe rupture caused by primary blast: a finite element analysis

Liu

Wang

et al. 2014

Computer Methods in Biomechanics and Biomedical Engineering

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Although a human eye comprises less than 0.1% of the frontal body surface area, injuries to the eye are found to be disproportionally common in survivors of explosions. This study aimed to introduce a Lagrangian-Eulerian coupling model to predict globe rupture resulting from primary blast effect. A finite element model of a human eye was created using Lagrangian mesh. An explosive and its surrounding air domain were modelled using Eulerian mesh. Coupling the two models allowed simulating the blast wave generation, propagation and interaction with the eye. The results showed that the peak overpressures caused by blast wave on the corneal apex are 2080, 932.1 and 487.3 kPa for the victim distances of 0.75, 1.0 and 1.25 m, respectively. Higher stress occurred at the limbus, where the peaks for the three victim distances are 25.5, 14.1 and 6.4 MPa. The overpressure threshold of globe rupture was determined as 2000 kPa in a small-scale explosion. The findings would provide insights into the mechanism of primary blast-induced ocular injuries.

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Retinal Sequelae of Primary Ocular Blast Injuries

Cited by 33 publications

References 3 publications

Primary Blast Injury to the Eye and Orbit: Finite Element Modeling

Primary Blast Injury to the Eye and Orbit: Finite Element Modeling

Acute vitreoretinal trauma and inflammation after traumatic brain injury in mice

Prediction of globe rupture caused by primary blast: a finite element analysis

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