Purchase this article with an account.
T. N. Hwang, T. J. McCulley; The Role of Intraorbital Shockwave Amplification in the Biomechanics of Indirect Traumatic Optic Neuropathy. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2484.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
In indirect traumatic optic neuropathy, force is transmitted from the point of impact to the optic nerve. Although the exact mechanism is not well elucidated, injury presumably occurs by force transmission through the bones. An alternate theory involves soft tissue "shockwave" amplification of a posteriorly propagating pressure wave. Consistent with this, previous work demonstrated high frequency oscillations consistent with reflected shockwave components within the soft tissues of cadaver orbits after anterior blunt trauma. To further investigate the possibility of shockwave amplification, we assess the fluidics of a pressure wave traversing the orbital space.
A synthetic (plastic) skull was submerged within a 80-liter water tank. Water waves were generated anterior to the skull using a rigid ball rolling down a ramp and striking a flexible membrane on the side of the tank. Pressure changes were recorded within and external to the orbit using commercial transducers (Measurement Specialties Model 154N-005A)
The mean increase in water pressure within the orbit, 1.42 +/- 0.04 psi, was significantly higher than that measured externally, 1.04 +/- 0.07 psi (p<0.0001 - two-tailed Student’s t-Test). In addition, higher frequency fluctuations (above 300 Hz) were recorded within the orbit but not externally.
Our data suggests that shockwave amplification may occur within the orbital space, consistent with traumatic optic nerve injury resulting from soft tissue force transmission/amplification.
This PDF is available to Subscribers Only