Research On The Correlation Between Lens Stress And Cortical Cataract Based On Finite Element Method

The cataract is formed when the lens changes from a normal transparent state to a cloudy state.Age-related cataracts are classified into cortical,nuclear,and posterior subcapsular cataracts according to areas of lens opacification,of which cortical cataracts are more common.The anatomy revealed that the outer boundary of the turbid area of the cortical cataract lens was 0.5 mm from the equator of the lens,and the turbid area of the cortex accounted for approximately 7.5% of the equator of the lens.This may be related to the amount of stress in the area during the adjustment.This study sought to investigate the relationship between the magnitude and distribution of lens stress and the formation of cortical cataracts.In this thesis,the finite element method was used to simulate the process of stretching the lens from the regulated state to the non-regulated state under physiological external forces in the body.In the created finite element model of the lens,the hyperelastic model of the lens changes according to the gradient was introduced.The stress of the lens under the external force was adjusted for the 11,29,45-year-old lens to adjust the external force needed to complete the process.And distribution,to explore whether there is a correlation between the lens stress and cortical cataract formation and the impact of the lens' s own components on the lens stress.It was found that there was a slight increase in the external force regulating the increase of the external force with age in the lens from the adjustment state to the non-regulation state,which is basically consistent with the study of Hermans et al;the 45-year-old lens has a larger area of stress in the cortical region.The distance from the edge of the equator to the border is approximately 0.33 mm,which accounts for 7.3% of the equator radius of the lens.The 11-and 29-year-old regions of high lens stress were basically the same as in the 45-year-old.The hyperelasticity shear modulus of the lens changes with space in any way.The area with a larger intra-lens stress is basically consistent with Michael's observation of the cortical opacity area;the lens material has a greater influence on the dynamic properties of the lens and is replaced by Young lens material,the lens stress is significantly reduced.Lens geometry has little effect on the mechanical properties of the lens.The increased thickness of the lens capsule has a protective effect on the lens.