ULTRASOUND CHARACTERIZATION OF NORMAL OCULAR TISSUE IN THE FREQUENCY-RANGE FROM 50 MHZ TO 100 MHZ

The ultrasonic properties of ocular tissues including sclera, cornea, ciliary body and iris have been quantitatively evaluated over the freq uency range from 50 MHz to 100 MHz at 37 degrees C. Measurements were made with a wideband 60 MHz PVDF copolymer transducer in conjunction w ith a C-scan microscopy system developed in our laboratory, Using this system, high resolution overview images were produced to identify hom ogeneous tissue regions for detailed quantitative analysis, The speed of sound for the four eye tissues ranged from 1542 m/s for iris to 162 2 m/s for sclera, At 50 MHz attenuation coefficient ranged from 1.3 dB /mm for cornea to 4.3 dB/mm for sclera, Scleral tissue also had the hi ghest backscatter coefficient (0.0157 Sr(-1)mm(-1)), while iris had th e lowest (0.00184 Sr(-1)mm(-1)). The measured ultrasonic properties ar e qualitatively related to their histological structure and imaging ch aracteristics.