According to the current results in a porcine eye model, FLC had less average resistance to capsule tear than CCC, but the weakest openings were seen in the CCC group.

Anterior capsule openings created at a high energy level were slightly weaker and less extensible than those created at low or intermediate levels, possibly due to the increased thermal effect of photo-disruption.

IntroductionThe eye is one of the most important sensory organs of the human body. The human eye is an almost spherical elastic organ with spatial elastic support. The properties of its components are always considerably age-related. There are several studies and numerical investigations which dealt with these subjects: Abolmaali et al. (2007) [1], Burd et al. (2002) [7] and Liu et al. (2006) [16]. The biomechanical model of a human eye consists of two basic systems: cornea-sclera with the ciliary muscle and crystalline lens. Each of the two systems is modelled separately due to their different purposes, but the complex modelling of the human eye is rare, despite of the fact that the surrounding parts can influence the results, such as the elastic bearing with the fatty tissue.We have built a complex three dimensional finite element model which contains the biologically and mechanically required parts for biomechanical analysis that we want to analyse.In this paper we do not use all the advantages of the complexity of our model, we only want to show one field that we can analyze with it. But we emphasize that it is unequivocal that if we want to analyze, for instance, the movement of nonsymmetric intraocular lens implantation or effects of blunt eye injuries, the 3D model is already indispensable.We have examined in this paper the accommodation problem based on the classical Helmholtz theory according to the age-related changes in geometry and materials. We note that there are several controversial other theories for accommodation (Schachar, Coleman, etc.), but based on the doctors' opinion from Semmelweis University, Department of Ophthalmology and other specialists (Burd et al.) [7] we accept the classical Helmholtz theory and we do not wish to go into the possibilities of applying different theories and debates. We describe the essence of Helmholtz theory later.To understand the problem, we have to discuss very shortly what the accommodation of the human eye is. To answer this question we have to look over the main parts of the eye: these are the sclera, the cornea, the ciliary muscle, the zonular fibres and the crystalline lens with nucleus, cortex and capsule (see Figure 1).

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Purpose: To evaluate and compare the mechanical resistance to tearing of the anterior lens capsule opening after staining with different concentrations of trypan blue in ex vivo porcine eyes. Setting: Semmelweis University, and Budapest University of Technology and Economics, Budapest, Hungary. Design: Experimental study. Methods: The study comprised 75 porcine eyes. The capsule was unstained in the Control Group (n = 25 eyes), 0.06% trypan blue was used to stain the capsule in Stained 1 Group (n = 25 eyes), and 0.1% trypan blue was used to stain the capsule in Stained 2 Group (n = 25 eyes). After capsulorhexis, the capsule openings were stretched with custom-designed testing equipment until they ruptured. The rupture force (RF), circumference stretching ratio (CSR), and secant modulus at 10 mN (SM10mN) and 50 mN (SM50mN) were evaluated. Results: In total, 75 eyes were enrolled. There were no statistically significant differences in the RF (P = .8924) or CSR (P = .3876) among the groups. There were no statistically significant differences in the SM10mN (P = .8215) or SM50mN (P = .4184) among the groups. Conclusions: In this porcine eye model, the trypan blue concentrations that are routinely used in cataract surgery had no effect on capsular rim stability.