Mechanical characterization of the vitreous body with acoustic radiation force

As we age, substantial mechanical and structural alterations occur in the vitreous. These changes are believed to induce a series of vision threatening conditions, including retinal detachment and nuclear sclerotic cataracts. We have developed an acoustic radiation force based technique called kinetic acoustic vitreoretinal examination (KAVE), which can be used to detect mechanical changes of the vitreous. We present results obtained by applying KAVE on human eyes in vivo. Experiments were conducted using a Philips SONOS 5500 imaging system employing a 5 MHz linear array. Within the current FDA ophthalmology intensity limits of 68 mW/cm², we observe in vivo displacements that ranged between 14 and 240 microns. Through the combination of appropriate mechanical modeling and signal processing, we are able to generate images of viscoelastic parameters.