A method for producing a lens for an ultrasound apparatus, the method comprising the steps of providing a barrier tissue model, a soft tissue model surrounded by the barrier tissue, and a coupling medium model, wherein the barrier tissue presents an acoustic impedance different from that of soft tissue; choosing a source point situated in the coupling medium model; choosing a predetermined wave frequency and wavelength, the predetermined frequency being comprised between 100 kHz and 20 MHz and the predetermined wavelength being determined by the predetermined frequency and a velocity of propagation of the wave in the coupling medium model; providing a treatment volume situated inside the barrier tissue model; providing a plurality of nodes distributed inside the treatment volume; simulating the emission of a spherical wave from each of the nodes of the plurality of nodes, creating a simulated wave front resulting from the superposition of the spherical waves, each spherical wave requiring an amplitude and a phase, there being at least two nodes with different amplitudes and/or phases, each spherical wave having the predetermined frequency; receiving the simulated wave front on a receiving surface which contains the source point; processing the results received on the receiving surface; on the basis of the processed results, designing a holographic lens surface which can generate a wave pattern equivalent to the simulated, time-reversed, wave front when it receives a wave from a planar, single-element emitter situated at the source point with the predetermined wave frequency and wavelengths; and three-dimensionally producing the design of the lens obtained in the corresponding step, the method being characterized in that the step of processing the results received on the receiving surface comprises dividing the receiving surface into pixels and analyzing the amplitude and phase of the wave received in each pixel, wherein the pixel size depends on the predetermined wavelength and wherein each pixel of the receiving surface is considered as a Fabry-Pérot type resonator which can resonate longitudinally, giving rise to a fragment of the lens, and in the step of designing the holographic lens surface equivalent heights are chosen for each fragment of the lens based on the amplitude and phase of the wave received in each pixel of the receiving surface. providing a barrier tissue model, a soft tissue model surrounded by the barrier tissue, and a coupling medium model, wherein the barrier tissue presents an acoustic impedance different from that of soft tissue; choosing a source point situated in the coupling medium model; choosing a predetermined wave frequency and wavelength, the predetermined frequency being comprised between 100 kHz and 20 MHz and the predetermined wavelength being determined by the predetermined frequency and a velocity of propagation of the wave in the coupling medium model; providing a treatment volume situated inside the barrier tissue model; providing a plurality of nodes distributed inside the treatment volume; simulating the emission of a spherical wave from each of the nodes of the plurality of nodes, creating a simulated wave front resulting from the superposition of the spherical waves, each spherical wave requiring an amplitude and a phase, there being at least two nodes with different amplitudes and/or phases, each spherical wave having the predetermined frequency; receiving the simulated wave front on a receiving surface which contains the source point; processing the results received on the receiving surface; on the basis of the processed results, designing a holographic lens surface which can generate a wave pattern equivalent to the simulated, time-reversed, wave front when it receives a wave from a planar, single-element emitter situated at the source point with the predetermined wave frequency and wavelengths; and three-dimensionally producing the design of the lens obtained in the corresponding step, the method being characterized in that the step of processing the results received on the receiving surface comprises dividing the receiving surface into pixels and analyzing the amplitude and phase of the wave received in each pixel, wherein the pixel size depends on the predetermined wavelength and wherein each pixel of the receiving surface is considered as a Fabry-Pérot type resonator which can resonate longitudinally, giving rise to a fragment of the lens, and in the step of designing the holographic lens surface equivalent heights are chosen for each fragment of the lens based on the amplitude and phase of the wave received in each pixel of the receiving surface.