Photodisruption of a thin membrane near a solid boundary: an in vitro study of laser capsulotomy

Abstract

A Nd:YAG laser photodisruption is a well-established tool for intraocular surgery, such as treatment of posterior capsule opacification that affects the visual function. During the intraocular procedure, called laser capsulotomy, the excitation pulse is focused several times just behind the posterior capsule and intraocular lens to create the central opening in the opacified capsule. We built an in-vitro experiment to (i) clarify the influence of the distance between the intraocular lens and the posterior capsule on the total-pulse energy required for the capsulotomy; and to (ii) investigate the main mechanisms responsible for the posterior-capsule opening. In our in-vitro model different distances between the solid boundary (imitating an intraocular lens) and the membrane (imitating the posterior capsule) simulate different types of posterior-capsule opacification. Our results show that procedure efficiency decreases by decreasing distance between the lens and the capsule. We also explain that for smaller distances between the pulse focus and the membrane, plasma and shock wave are responsible for the capsule disruption. Here, a risk for collateral damage significantly increases. On contrary, the membrane and the bubble jet disrupt the membrane, when pulse focus is moved away and the risk for intraocular-lens damage decreases. However, the membrane disruption is not very effective, if it is placed near the solid boundary that inhibits the membrane jet.

Propulsion effects after laser ablation in water, confined by different geometries

“…The aim of this work is to study the propulsion effects during pulsed laser ablation in liquids [13] that is important for diversity of applications, including nanoparticle generation [14,15], laserinduced forward transfer [16,17], laser shock peening [18][19][20] and different laser medical applications [21][22][23]. The propulsion effects are investigated for different shapes of a blind hole filled with different volumes of water.…”

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

“…The description of the wave propagation and superposition is similar to the previous case, with a few differences. The source is now closer to the front of the eye, approximately in the center of the curvature of the cornea [31]. The radius of curvature of the wavefront arriving at the reflecting boundary is practically the same as the radius of curvature of the boundary itself.…”

Laser-induced bubble dynamics inside and near a gap between a rigid boundary and an elastic membrane

“…In the study of laser capsulotomy by (Hawlina et al, 2016) the authors showed that in the case of a wider gap between the intraocular lens and the posterior capsule fewer laser pulses were needed to achieve the desired rupture of the capsule. This observation is consistent with the findings of this paper, where most pronounced interaction between the bubble and the membrane was observed in the case gap size which was large compared to bubble radius.…”