Elastic constants of the human lens capsule
- 1 March 1969
- journal article
- Published by Wiley in Journal Of Physiology-London
- Vol. 201 (1), 1-19
- https://doi.org/10.1113/jphysiol.1969.sp008739
Abstract
1. A technique is described whereby the elasticity of the human lens capsule has been determined at birth and throughout life. This technique requires three separate determinations: (a) thickness; (b) stress and strain; (c) Poisson's ratio; (a) the capsule was clamped between accurately perforated ground glass plates and its thickness determined by noting the change in depth of focus between Latex spherules adhering to its upper and lower surfaces; (b) the undisturbed capsule was then placed in a specially designed glass distension apparatus and the relationship between volume and pressure recorded when it was distended with isotonic saline. The permeability of the capsule was also measured; (c) in some cases Poisson's ratio was determined by measuring the change of thickness of the capsule and the height to which it rose when distended with isotonic saline at different pressures. An apparatus was designed for this purpose.2. The average thickness of the anterior capsule increases from birth until about the 60th year but thereafter it decreases slightly.3. Poisson's ratio was about 0.47 for both cat and human capsule, and no significant variations with age in human capsule could be detected.4. Corrected volume pressure curves obeyed Hook's law almost to the point of capsule rupture.5. In childhood Young's Modulus of elasticity is about 6 x 10(7) dyn/cm(2) and decreases to 3 x 10(7) dyn/cm(2) at 60 and 1.5 x 10(7) dyn/cm(2) in extreme old age.6. The ultimate tensile stress was 2.3 x 10(7) dyn/cm(2) in young capsules and 0.7 x 10(7) dyn/cm(2) in old ones. The maximum percentage elongation was 29 per cent and independent of age.7. The implications of these findings are discussed in relation to(a) the mechanical properties of the lens capsule;(b) the ageing of the lens capsule and basement membranes; and(c) the decrease in elasticity of the lens capsule as a cause of presbyopia.This publication has 5 references indexed in Scilit:
- Variation with Age in Elasticity of Skin and Subcutaneous Tissue in Human IndividualsJournal of Gerontology, 1962
- Aortic elastic tissue; isolation with use of formic acid and discussion of some of its properties.1958
- STUDIES ON THE ANTIGENIC STRUCTURE OF THE EYE USING THE FLUORESCENT ANTIBODY TECHNIQUEBritish Journal of Ophthalmology, 1957
- Relation of Structure to Function of the Tissues of the Wall of Blood VesselsPhysiological Reviews, 1954
- Passage of Molecules Through Capillary WallsPhysiological Reviews, 1953