Ultrasound surface wave elastography of the living human eye

The purpose of this paper was to demonstrate a noninvasive technique to measure elastic properties of human eyes using ultrasound surface wave elastography (USWE) technique. Twenty eyes of 10 healthy subjects (age 44–63; mean 51 years) were studied. A localized harmonic vibration for 0.1 second at 100 Hz was generated by using a spherically-tipped vibrator (3 mm diameter) placed on the closed eyelid. The subjects only felt a gentle vibration on their eyes. The wave propagation in the eye was measured by using a linear array ultrasound transducer. The wave speed was determined from the change in phase with distance. Mean wave speed in the cornea was 1.82 ± 0.10 m/s (± SD) at 100 Hz. Intraocular pressure (IOP) was measured by using Goldmann applanation tonometry. Mean IOP was 12.8 ± 2.7 mmHg (± SD). The wave speed correlated well with IOP (r=0.74; p<0.001). USWE is a safe and noninvasive technique for generating and measuring wave propagation in the eye. Further improvement and validation of USWE in the eye experiments is needed.