ELASTIC CONSTANTS OF HUMAN LENS CAPSULE
ELASTIC CONSTANTS OF HUMAN LENS CAPSULE
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DOI：
10.1113/jphysiol.1969.sp008739
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发表时间：
1969-01-01
影响因子：
5.5
通讯作者：
FISHER, RF
中科院分区：
文献类型：
--
作者：
FISHER, RF
1.描述了一种技术，由此在出生时和整个生命中确定了人透镜囊的弹性。该技术需要三个独立的测定：（a）厚度;（B）应力和应变;（c）泊松比;（a）将胶囊夹在精确穿孔的毛玻璃板之间，通过记录粘附在其上表面和下表面的乳胶小球之间的焦深变化来测定其厚度;（B）然后将未受干扰的胶囊置于专门设计的玻璃扩张装置中，并且当用等渗盐水扩张时记录体积和压力之间的关系。还测量了胶囊的渗透性;（c）在某些情况下，通过测量胶囊厚度的变化和在不同压力下用等渗盐水扩张时胶囊上升的高度来确定泊松比。为此目的设计了一个装置。前囊平均厚度从出生到60岁左右逐渐增加，以后略有减少.猫和人被膜的泊松比均约为0·47，人被膜的泊松比随年龄变化不明显.修正后的容积压力曲线在囊膜破裂点附近基本符合Hook定律.在儿童时期，杨氏弹性模量约为6 × 107 dyn/cm 2，在60岁时降至3 × 107 dyn/cm 2，在极老年时降至1·5 × 107 dyn/cm 2。年轻胶囊的极限拉伸应力为2.3 × 107 dyn/cm 2，老年胶囊的极限拉伸应力为0.7 × 107 dyn/cm 2。最大延伸率为29%，与年龄无关。这些研究结果的影响进行了讨论有关（a）的透镜胶囊的机械性能;（B）老化的透镜胶囊和基底膜;和（c）减少弹性的透镜胶囊作为老花眼的原因。
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 × 107dyn/cm2and decreases to 3 × 107dyn/cm2at 60 and 1·5 × 107dyn/cm2in extreme old age.6. The ultimate tensile stress was 2·3 × 107dyn/cm2in young capsules and 0·7 × 107dyn/cm2in 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.