[Characteristics of propagation of focused ultrasound through the eye structures]

Experimental data obtained from studies of the effects of various structures of the animal eye on the transmission of focused ultrasonic beam are presented. Method based on the use of focused transducers as ultrasonic receivers, angle aperture of the receiver being equal (or more) to that of the radiator, is suggested to carry out remote measurements of spatial distribution of acoustic pressure inside the eye. It is shown that together with the movements of the radiator focus towards the eye centre the convergent beam defocuses while the maximum broadening of the central lobe of the acoustical pressure distribution function reaches 40-50% at the crystalline lens exit, while the peak intensity reduction is 40%. As a result the average intensity across the focal spot has become 3 times less. The effects observed are the result of the influence of the crystalline lens which has the properties of the effective acoustic dispersing lens.