Hatami-Marbini Hamed, Rahimi Abdolrasol
From the Computational Biomechanics Laboratory, School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma, USA.
From the Computational Biomechanics Laboratory, School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma, USA.
J Cataract Refract Surg. 2015 Mar;41(3):644-51. doi: 10.1016/j.jcrs.2014.07.029. Epub 2015 Feb 21.
To determine effects of hydration on tensile stress-relaxation behavior of the bovine cornea.
Computational Biomechanics Laboratory, School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma, USA.
Experimental study.
Bovine corneal strips were obtained from a local slaughterhouse and divided into 6 groups based on their thickness. The samples were first air dried and then rehydrated to reach the predetermined thickness of each group as follows: 0.4 mm (Group 1), 0.5 mm (Group 2), 0.7 mm (Group 3), 0.9 mm (Group 4), 1.1 mm (Group 5), and 1.5 mm (Group 6). A custom-built tensile machine was used to characterize the stress-relaxation properties. Mineral oil was used as the bathing fluid to prevent hydration variation during the experiments.
Hydration significantly affected the immediate and transient tensile behavior of the cornea. With increasing hydration, there was a significant decrease in peak and equilibrium stress (P < .01). At all hydration levels, the tensile stress-strain curves and relaxation behavior were numerically represented with exponential and logarithmic mathematical expressions (R(2) > 0.99), respectively. An exponential relationship was found between the tangent modulus and hydration.
Hydration of the corneal strips significantly affected their tensile and viscoelastic mechanical behavior. Therefore, while careful attention must be taken in interpreting the results in previous studies in which hydration of specimens was not fully controlled, it is important to monitor and report hydration of corneal samples in future studies.
Neither author has a financial or proprietary interest in any material or method mentioned.
确定水合作用对牛角膜拉伸应力松弛行为的影响。
美国俄克拉何马州斯蒂尔沃特市俄克拉何马州立大学机械与航天工程学院计算生物力学实验室。
实验研究。
从当地屠宰场获取牛角膜条，并根据其厚度分为6组。样品先进行空气干燥，然后再水化至每组预定的厚度，如下：0.4毫米（第1组）、0.5毫米（第2组）、0.7毫米（第3组）、0.9毫米（第4组）、1.1毫米（第5组）和1.5毫米（第6组）。使用定制的拉伸机来表征应力松弛特性。使用矿物油作为浴液，以防止实验过程中的水合变化。
水合作用显著影响角膜的即时和瞬时拉伸行为。随着水合作用的增加，峰值应力和平衡应力显著降低（P <.01）。在所有水合水平下，拉伸应力-应变曲线和松弛行为分别用指数和对数数学表达式进行数值表示（R²> 0.99）。发现切线模量与水合作用之间存在指数关系。
角膜条的水合作用显著影响其拉伸和粘弹性力学行为。因此，在解释之前未充分控制标本水合作用的研究结果时必须谨慎，而在未来的研究中监测和报告角膜样品的水合作用非常重要。
两位作者均对文中提及的任何材料或方法没有财务或专有利益。
