April 2014
Volume 55, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2014
Computational Modeling of Internal Eye Injury due to Primary Blast
Author Affiliations & Notes
  • Richard Watson
    Biomedical Engineering, The University of Texas at San Antonio, San Antonio, TX
    Biodynamic Research Corporation, San Antonio, TX
  • Walter Gray
    Geological Sciences, The University of Texas at San Antonio, San Antonio, TX
  • Randolph D Glickman
    Biomedical Engineering, The University of Texas at San Antonio, San Antonio, TX
    Ophthalmology, UTHSCSA, San Antonio, TX
  • Brian J Lund
    U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, San Antonio, TX
  • William Eric Sponsel
    Biomedical Engineering, The University of Texas at San Antonio, San Antonio, TX
    Visual Science, Rosenberg School of Optometry; UIW, San Antonio, TX
  • Matthew Aaron Reilly
    Biomedical Engineering, The University of Texas at San Antonio, San Antonio, TX
  • Footnotes
    Commercial Relationships Richard Watson, None; Walter Gray, None; Randolph Glickman, None; Brian Lund, None; William Sponsel, None; Matthew Reilly, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science April 2014, Vol.55, 4453. doi:
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      Richard Watson, Walter Gray, Randolph D Glickman, Brian J Lund, William Eric Sponsel, Matthew Aaron Reilly, ; Computational Modeling of Internal Eye Injury due to Primary Blast. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4453.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract
 
Purpose
 

Ocular trauma has increased from 0.6% to 6% of battlefield injuries over the last 140 years. Recent physical experiments have demonstrated that primary blast can produce significant ocular injury at low levels of overpressure. In most cases, the mechanisms of internal injury are obscured due to the difficulty of imaging inside the eye during the blast event. Alternatively, computational modeling can provide invaluable insight as to the internal dynamics and forces occurring inside the eye under primary blast conditions.

 
Methods
 

Numerical simulations of primary blast to porcine eyes were used to support a series of in vitro shock tube experiments. Sub-globe rupture levels of blast (overpressures from 50 - 200 kPa) were used in experiments and modeling. Three dimensional Lagrangian Finite Element Analysis (FEA) models were created using material properties from the relevant literature. Internal structures of the eye were modeled in detail to allow visualization of internal dynamics under blast conditions. Experimental and hypothetical blast waveforms with purely positive and purely negative pressure components were applied to give insights as to the relative contributions of each to the observed trauma.

 
Results
 

FEA models predicted increasing levels of force, distortion, and strain with increasing blast energy. This is consistent with the experimental finding that likelihood and severity of injury increases with blast energy. Although not visible in the experiments, computational results suggest compression of the peripapillary retina is a potential injury mechanism even at low blast energies (Fig 1).

 
Conclusions
 

FEA models confirmed the potential for primary blast ocular injury. The models suggest that different injuries are associated with the different phases of the blast profile. Specifically, posterior segment damage is associated with the positive phase and anterior segment damage (angle recession) is associated with the negative phase (Fig. 2). Computational results correlated with the physical experiments providing insight into injury mechanisms not observable in the experiments. Thus, FEA modeling is an essential supplement to physical experiments.

 
 
Figure 1. Change in peripapillary retinal thickness as a function of peak overpressure
 
Figure 1. Change in peripapillary retinal thickness as a function of peak overpressure
 
 
Figure 2. Undeformed porcine eye geometry (left). Deformed geometry and stress distribution in sclera when subjected to negative phase of a hypothetical blast wave (right).
 
Figure 2. Undeformed porcine eye geometry (left). Deformed geometry and stress distribution in sclera when subjected to negative phase of a hypothetical blast wave (right).
 
Keywords: 473 computational modeling • 742 trauma • 697 retinal detachment  
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