AUTHOR=DeMar James , Sharrow Keith , Hill Miya , Berman Jonathan , Oliver Thomas , Long Joseph 

TITLE=Effects of Primary Blast Overpressure on Retina and Optic Tract in Rats

JOURNAL=Frontiers in Neurology

VOLUME=Volume 7 - 2016

YEAR=2016

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2016.00059

DOI=10.3389/fneur.2016.00059

ISSN=1664-2295

ABSTRACT=Blast has been the leading cause of injury, particularly traumatic brain injury and visual system injury, in combat operations in Iraq and Afghanistan. We determined the effect of shock tube-generated primary blast on retinal electrophysiology and on retinal and brain optic tract histopathology in a rat model.

The amplitude of a- and b- waves on the electroretinogram (ERG) for both right and left eyes were measured prior to a battlefield-simulation Friedlander-type blast wave and on 1, 7, and 14 days thereafter. Histopathologic findings of the right and left retina and the right and left optic tracts (2.8 mm post-optic chiasm) were evaluated 14 days after the blast.

For two experiments in which the right eye was oriented to the blast, the amplitude of ERG a- and b-waves at 7 days post-blast on the right side but not on the left side was diminished compared to that of sham animals (P=0.005-0.01)  Histopathologic injury scores at 14 days post-blast for the right retina but not the left retina were higher than for sham animals (P=0.01), and histopathologic injury scores at 14 days for both optic tracts were markedly higher than for shams (P < 0.0001). 

Exposure of one eye to a blast wave, comparable to that causing human injury, produced injury to the retina as determined by ERG and histopathology, and to both post-chiasmatic optic tracts as determined by histopathology. This model may be useful for analyzing the effect of therapeutic interventions on retinal damage due to primary blast waves.