June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Long-term functional and structural consequences of primary blast injury to the eye
Author Affiliations & Notes
  • Cara Tessia Motz
    Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Atlanta, Georgia, United States
  • Rachael S Allen
    Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Atlanta, Georgia, United States
  • Andrew Feola
    Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
    Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Atlanta, Georgia, United States
  • Kyle Chesler
    Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
  • Raza Haider
    Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Atlanta, Georgia, United States
  • Sriganesh Ramachandra Rao
    Ophthalmology, Biochemistry, & Neuroscience Program, SUNY- University at Buffalo, Buffalo, New York, United States
  • Lara Skelton
    Research Service, VA Western NY Healthcare System, Buffalo, New York, United States
  • Steven J Fliesler
    Ophthalmology, Biochemistry, & Neuroscience Program, SUNY- University at Buffalo, Buffalo, New York, United States
    Research Service, VA Western NY Healthcare System, Buffalo, New York, United States
  • Machelle T Pardue
    Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Atlanta, Georgia, United States
    Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
  • Footnotes
    Commercial Relationships   Cara Motz, None; Rachael Allen, None; Andrew Feola, None; Kyle Chesler, None; Raza Haider, None; Sriganesh Ramachandra Rao, None; Lara Skelton, None; Steven Fliesler, None; Machelle Pardue, None
  • Footnotes
    Support  5IO1 BX002439 (SJF, MTP), RPB Unrestricted Grant (SJF), Dept. of Veteran Affairs facilities and resources (SJF, MTP); Dept of Veterans Affairs Rehab R&D Service, Research Career Scientist Award (C9257-5)
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 1763. doi:
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    • Get Citation

      Cara Tessia Motz, Rachael S Allen, Andrew Feola, Kyle Chesler, Raza Haider, Sriganesh Ramachandra Rao, Lara Skelton, Steven J Fliesler, Machelle T Pardue; Long-term functional and structural consequences of primary blast injury to the eye. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1763.

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

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Abstract

Purpose : Patients with primary blast injury (PBI) often present with delayed visual deficits of unknown etiology. In this study, we evaluated longitudinal changes in retinal function and morphology following acoustic blast exposure, using a rat model of PBI.

Methods : Adult male Long-Evans rats (N=10-12/group) were exposed to a single acoustic blast (63 kPa, 195 dB-SPL) at 3.5 mo of age, using a shock tube device. The blast was directed at the right eye only, perpendicular to the body axis, with only the head exposed. Non-blasted, age-matched rats served as controls. Animals were tested longitudinally at 2, 4, 6 and 8 mo post-blast for: retinal function with electroretinography (ERG); contrast sensitivity (CS) and spatial frequency (SF) thresholds with optokinetic tracking (OKT); and retinal structure with spectral domain-optical coherence tomography (SD-OCT). At 8 mo post-blast, animals were sacrificed and tissues were taken for future biochemical and immunohistochemical analyses. Statistical analysis: repeated measures two-way ANOVA (significance: p<0.05).

Results : CS thresholds were consistently decreased in both eyes of blast-exposed animals vs. controls across time (p<0.001), and the blasted eyes had significantly lower CS thresholds than the contralateral eyes (e.g., at 8 mo post-blast: Δ = 45%; p<0.001). Blasted eyes also showed a 20% decrease in SF thresholds compared to contralateral and control eyes (p<0.001), at all time points. ERG scotopic a- and b-wave amplitudes were substantially greater (p<0.001) and b-wave implicit times were increasingly delayed (e.g., 18% at 8 mo; p<0.001) in blast-exposed rats, relative to controls. Similar trends were observed for photopic flicker responses. SD-OCT showed increased total retinal thickness, relative to controls, in both eyes of blast-exposed rats across all time points (5% at 8 mo; p<0.01), with inner nuclear layer and inner/outer segment layers being the major contributors.

Conclusions : PBI can manifest with functional and structural changes to the retina that are counter-intuitive and atypical of common retinal diseases. Here, blast exposure compromised visual function, yet ERG amplitudes were supranormal, with delayed implicit times, suggesting disruption of inhibitory signaling pathways. Rather than degenerative thinning, retinal thickness of blast-exposed eyes was greater than normal. The underlying mechanisms for these changes remain to be determined.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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