Abstract
Purpose :
To investigate the long-term effects of varying blast overpressure (BOP) on pathophysiology and behavioural outcome. The goal of this study was to correlate blast overpressure readings to the pathophysiological and neurobehavioural outcomes induced by primary BOP using a NHP non-lethal blast model.
Methods :
The underlying mechanism for primary blast injury is still unclear. In the proposed study, detailed retinal imaging scans and retinal function test was carried out before and after BOP injuries on NHP (n =20; 40 eyes). Retinal pathological changes were monitored by fundus fluorescein angiography, spectral domain Optical Coherence Tomography (OCT), anterior segment in vivo slit lamp microscopy, in vivo confocal microscopy, and anterior segment-OCT (AS-OCT). Roland Consult Electrophysiological Units was utilized for complete retinal function test, which includes Visual Evoked Potential / ElectroRetinoGraphy / Electro-OculoGram / multifocal ElectroRetinoGram.
Results :
Morphological changes in cornea and retina were analyzed using OCT images. Overall retinal defects, hemorrhage and optic head was examined by Fundus images. We have observed increased corneal thickness 24 hours after blast which may be due to incidences of corneal edema observed in some NHPs post injury. 25% showed optic nerve head damage at all time points (p = 0.003). Macular thickness longtidudinal profile, showing signification changes at 2 months after injury (p = 0.0122) which was resolved 4 months after blast. Retinal function test showed that there was a slight change in visual acuity, patternERG and mfERG in high pressure as compared to control eye.
Conclusions :
Macular thickness showed biphasic changes, increasing at 2 months post-blast, and subsequently recovered at the 4-month time-point. Remarkable structural alterations affecting Purkinje neurons and glial cells were observed at 1 week after blast. Lipofuscin accumulation is a major risk factor implicated in optic head damage, a degenerative disease of the eye. The ability to non-invasively profile these retinal structural and functional changes after blast may help us understand the effects of BOP on retinal injury and also provide a useful tool for assessment of Mild traumatic brain injury (MTBI).
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.