Dick H B, Krummenauer F, Augustin A J, Pakula T, Pfeiffer N
Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.
J Cataract Refract Surg. 2001 Feb;27(2):320-6. doi: 10.1016/s0886-3350(00)00482-x.
To compare the rheological characteristics of a viscoadaptive viscoelastic formulation with those of 2 standard ophthalmic viscosurgical devices (OVDs).
Department of Ophthalmology, Johannes Gutenberg-University, and Max Planck-Institute for Polymer Research, Mainz, Germany.
An independent comparative study of 3 OVDs of sodium hyaluronate (Healon(R), Healon GV(R), and Healon(R)5) was performed using the Advanced Rheometric Expansion System to analyze rheologic behavior (eg, dynamic frequency dependence of the complex viscosity) as well as rheological parameters (eg, viscosity at zero shear rate, pseudoplasticity, relaxation time, elastic and viscous modulus).
Mean viscosity at zero shear rate was 243 Pas +/- 5 (SD) for Healon, 2451 +/- 12 Pas for Healon GV, and 5525 +/- 14 Pas for Healon5. Mean pseudoplasticity was 173 +/- 7, 754 +/- 10, and 591 +/- 6, respectively. Mean relaxation time was 21 +/- 3 sec, 83 +/- 4 sec, and 88 +/- 6 sec. At low shear rates, viscosity and elasticity (elastic and viscous modulus) increased from Healon through Healon5. Healon5 exhibited a dynamic behavior of the complex viscosity dependent on the duration of the shear rate exposure: At low shear rates, it slowly built up a high viscosity. At higher shear rates, it demonstrated a lower viscosity that decreased further during constant exposure to a specific shear rate.
Healon5 had the highest viscosity and elasticity when exposed to low and high shear rates. These characteristics maintain anterior chamber depth. Also, the high viscosity of Healon5 exhibited a dynamic frequency dependence. In the presence of turbulence and phaco power (continuous high shear rates), it became dispersive by fragmentation and formed a cavity with an outer retentive shell. The cohesive and dispersive properties of Healon5 make it the best of the 3 OVDs evaluated for use at all stages of phacoemulsification.
比较一种黏弹性自适应黏弹性制剂与两种标准眼科黏弹剂（OVDs）的流变学特性。
德国美因茨约翰内斯·古登堡大学眼科系和马克斯·普朗克聚合物研究所。
使用高级流变扩展系统对3种透明质酸钠OVDs（Healon®、Healon GV®和Healon®5）进行独立比较研究，以分析流变行为（如复数黏度的动态频率依赖性）以及流变参数（如零剪切速率下的黏度、假塑性、松弛时间、弹性模量和黏性模量）。
Healon在零剪切速率下的平均黏度为243 Pas±5（标准差），Healon GV为2451±12 Pas，Healon5为5525±14 Pas。平均假塑性分别为173±7、754±10和591±6。平均松弛时间为21±3秒、83±4秒和88±6秒。在低剪切速率下，黏度和弹性（弹性模量和黏性模量）从Healon到Healon5逐渐增加。Healon5表现出复数黏度的动态行为取决于剪切速率暴露的持续时间：在低剪切速率下，它会缓慢建立高黏度。在较高剪切速率下，它表现出较低的黏度，在持续暴露于特定剪切速率期间会进一步降低。
Healon5在低剪切速率和高剪切速率下具有最高的黏度和弹性。这些特性可维持前房深度。此外，Healon5的高黏度表现出动态频率依赖性。在存在湍流和超声乳化功率（持续高剪切速率）的情况下，它会因破碎而分散，并形成一个带有外部保留壳的腔。Healon5的内聚性和分散性使其成为在超声乳化所有阶段使用的3种OVDs中最佳的一种。
