Simulation of wave propagation inside a human eye: acoustic eye model (AEM)

Abstract

The article relates to SPS Operation entitled Building blocks, tools and systems for future factories -GOSTOP.

High-speed photography of shock waves with an adaptive illumination

“…Four probe pulses with constant intrapulse delay illuminated the converging shock wave, clearly locating the acoustic focus (Fa). An interesting phenomenon was captured, i.e., the Gouy phase shift of π , characteristic for spherical focusing of the pressure waves after they had already overpassed the focus [30,31].…”

Pressure wave focusing effects following laser medical procedures in human eyes

“…The location of the focal volume and the depth of focus depend both on the propagation characteristics, as well as on the size and spatiotemporal shape of the source. When focused, the pressure amplitude may well surpass the threshold for the potentially tissue damaging effects [3][4][5][6][7]. From the standpoint of tissue damage, the negative pressure (rarefactional waves) presents larger risk than the positive (compressional waves) [4].…”

Cavitation induced by shock wave focusing in eye-like experimental configurations

“…When the shock wave reaches the cornea-air or cornea-lens interface, the compressional wave reflects either as a rarefaction and changes its phase (example: cornea-air) or it remains a compression (example: cornea-lens) depending on the acoustic impedances of both media [16]. Figure 1(c) shows the reflection of the shock wave from the cornea-air interface, where the positive pressure is marked by a solid line and negative pressure by a dashed line.…”

“…The rest of the shock wave continues to propagate into soft tissues surrounding the eye. Due to comparable acoustic impedances of eye tissues, negligible reflections are expected at tissue boundaries [16]. Isolated bubbles are formed inside the frontal part of the anterior laser cone already overpassed by the reflected shock wave.…”

“…Close inspection of the shock wave after it has already passed the acoustic focus reveals a bipolar shape. This is a consequence of a Gouy phase shift the wave experiences after passing the focus [16].…”