Detection of intraocular pressure change in the eye using sonoelastic Doppler ultrasound.

We report the first use of sonoelastic Doppler ultrasound for in vivo and in vitro clinical studies of intraocular pressure (IOP). The method involves low-amplitude and low-frequency sonic excitation of the eye, and detection of the resulting vibration using Doppler ultrasound. A dependence of the frequency of resonance of the eye on the IOP has been observed in both in vitro and in vivo experiments. Preliminary in vitro experiments have been performed using eviscerated and enucleated human and pig eyes. As little as 4 mm Hg change in IOP has been found detectable in these experiments. Preliminary in vivo experiments also showed promising results in this regard. We present a simple model for the resonances of the eye, a method to detect the amplitude of vibration using Doppler ultrasound and results from the in vitro and in vivo experiments.