Ultrasound characterization of normal ocular tissue in the frequency range from 50 MHz to 100 MHz

Abstract

The ultrasonic properties of ocular tissues including sclera, cornea, ciliary body and iris have been quantitatively evaluated over the frequency range from 50 MHz to 100 MHz at 37/spl deg/C. Measurements were made with a wideband 60 MHz PVDF copolymer transducer in conjunction with a C-scan microscopy system developed in the authors' laboratory. Using this system, high resolution overview images were produced to identify homogeneous tissue regions for detailed quantitative analysis. The speed of sound for the four eye tissues ranged from 1542 m/s for iris to 1622 m/s for sclera. At 50 MHz the attenuation coefficient ranged from 1.3 dB/mm for cornea to 4.3 dB/mm for sclera. Scleral tissue also had the highest backscatter coefficient (0.0157 Sr/sup -1/ mm/sup -1/), while iris had the lowest (0.00184 Sr/sup -1/ mm/sup -1/). The measured ultrasonic properties are qualitatively related to their histological structure and imaging characteristics.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>