Ulster University Logo

Ulster Institutional Repository

Modeling internal stress distributions in the human lens: Can opponent theories coexist?

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Belaidi, A. and Pierscionek, B. K. (2007) Modeling internal stress distributions in the human lens: Can opponent theories coexist? JOURNAL OF VISION, 7 (11). p. 1. [Journal article]

Full text not available from this repository.

DOI: 10.1167/7.11.1

Abstract

The effects of material properties and equatorial stretching forces on the stress distribution and shape pro. le of human lenses were investigated to see whether support could be found for either or both current theories of accommodation. Finite element analysis was used to create models using shape parameters and material properties from published data. Models were constructed for two lenses of different ages. Material properties were varied to show differences between models with a single elastic modulus and those with different moduli for the cortex and the nucleus. Two levels of stretching forces were applied at the equator. Comparisons between experimental and model profiles were made, and stress distribution patterns were constructed. In all models, stretching produces a flattening in the peripheral curvature of the lens. In the younger lens, model and experimental results show that central curvature at some points is steeper for stretched than for unstretched profiles. In the older lens, gradients are flatter at all central points for stretched model and experimental profiles compared to the unstretched profile. In all models, there is a region of higher stress distribution within the lens that corresponds with the position of an infection point that appears on the anterior surface and, in the older lens, also on the posterior surface. The results show that equatorial stretching forces can produce shape changes in support of both current theories of accommodation depending on the lens age, shape, and applied force.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Biomedical Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Vision
ID Code:7616
Deposited By:Professor Barbara Pierscionek
Deposited On:18 Jan 2010 09:46
Last Modified:18 Jan 2010 09:46

Repository Staff Only: item control page