The influence of the shear-thinning properties on tear dynamics is analyzed using 2D numerical simulations. The simulations were conducted in conditions close to those of the actual tear film dynamics. The paper deals with the spreading of the shear-thinning tear film on a spherical cornea with blinking. The shear-thinning properties are described using Cross’s rheological model, known as the model that describes well shear-thinning properties of actual tears. We solved the continuity and the momentum equations using the mono-fluid formulation and the volume of fluid (VOF) method. We have examined the influence of rheological properties namely, the time constant, the zero shear viscosity, and the flow behavior index on the tear film profile. The results confirm that the curvature delays the risk of film rupture. The results also indicate that the values of the shear-thinning parameters within the range of the values measured in-vivo are the ones that delay tear-film breakup. These values provide quasi-uniform thin tear film and ensure a low wall shear stress lubrication between the moving eyelid and the cornea surface. The suggested values for the shear-thinning parameters can serve as a starting point for designing efficient artificial tears to alleviate moderate symptoms of dry eye syndrome.

使用二维数值模拟分析了剪切稀化特性对撕裂动力学的影响。模拟是在接近实际泪膜动力学的条件下进行的。该论文讨论了剪切变薄泪膜在眨眼的情况下在球形角膜上的扩散。剪切稀化特性使用 Cross 流变模型进行描述，该模型被称为描述实际眼泪的良好剪切稀化特性的模型。我们使用单流体公式和流体体积 (VOF) 方法求解了连续性和动量方程。我们已经检查了流变特性的影响，即时间常数、零剪切粘度和流动行为指数对泪膜轮廓的影响。结果证实，曲率延迟了膜破裂的风险。体内是延迟泪膜破裂的那些。这些值提供准均匀的薄泪膜并确保移动眼睑和角膜表面之间的低壁剪切应力润滑。剪切稀化参数的建议值可以作为设计有效人工泪液以减轻干眼症的中度症状的起点。