Soft contact lenses are medical devices made from aqueous polymeric gels that are worn on the eye to correct refractive errors. These devices interrupt the natural contact pairing between the cornea and the eyelid and create two interfaces comprised of a synthetic material and the epithelia—contact lens surfaces versus (1) the cornea and (2) the eyelid conjunctiva. The cellular responses to friction and shear stress are thought to contribute to contact lens discomfort. This study performs direct contact shear experiments using in vitro biotribological experiments using a microtribometer equipped with a hydrogel membrane probe. Sections from commercial contact lenses are held in place on a spherically capped membrane probe during reciprocating sliding experiments against confluent monolayers of living human telomerase-immortalized corneal epithelial cells (hTCEpi). The contact lenses were loaded against the cell monolayers to physiological contact pressures between 400 and 1300 Pa under an applied load of 200 µN. The reciprocating distance was 3 mm, at a sliding speed of 1 mm/s, and the maximum duration of sliding was 1000 cycles. Five commercially available lenses (somofilcon A, stenfilcon A, etafilcon A, verofilcon A, and delefilcon A) were used to evaluate the cell layer responses to aqueous gels of differing composition, surface modulus, and lubricity. Cell damage was measured via propidium iodide staining and in situ fluorescence microscopy. The shear stresses varied from 16 ± 2 Pa (delefilcon A and verofilcon A) to 86 ± 12 Pa (stenfilcon A), and cell damage increased with increasing shear stress and increasing sliding duration. The two lens materials that have high water content surface gel layers (delefilcon A and verofilcon A) showed distinctly lower measures of cell damage as compared to the other lenses. Surface gel layers with a large polymer mesh size and high water content are shown to be an effective approach to lower the contact pressure, lower the friction coefficient, and thereby lower the shear stress and cell damage.

软性隐形眼镜是一种由水性聚合物凝胶制成的医疗设备，可将其戴在眼睛上以矫正屈光不正。这些设备中断了角膜和眼睑之间的自然接触配对，并创建了两个由合成材料和上皮组成的界面-角膜接触镜表面与（1）角膜和（2）眼睑结膜。细胞对摩擦和剪切应力的反应被认为导致隐形眼镜不适。这项研究使用配备水凝胶膜探针的微摩擦计，通过体外生物摩擦学实验进行直接接触剪切实验。在对活的人类端粒酶永生化角膜上皮细胞（hTCEpi）的汇合单层进行往复滑动实验期间，将商用隐形眼镜的切片固定在球形盖膜探针上。在施加的200 µN的载荷下，将隐形眼镜顶在细胞单层上，使其生理接触压力在400至1300 Pa之间。往复距离为3 mm，滑动速度为1 mm / s，最大滑动持续时间为1000个循环。使用五种市售镜片（somofilcon A，stenfilcon A，etafilcon A，verofilcon A和delefilcon A）评估细胞层对不同成分，表面模量和润滑性的水性凝胶的反应。通过碘化丙啶染色和原位荧光显微镜测量细胞损伤。剪切应力从16±2 Pa（德立菲康A和维罗非康A）变化到86±12 Pa（司替非康A），并且随着剪切应力的增加和滑动时间的延长，细胞损伤也增加。与其他镜片相比，具有高水含量表面凝胶层的两种镜片材料（Delefilcon A和Verofilcon A）显示出明显更低的细胞损伤测量值。具有大的聚合物筛孔尺寸和高水含量的表面凝胶层被证明是降低接触压力，降低摩擦系数，从而降低剪切应力和细胞损伤的有效方法。与其他镜片相比，具有高水含量表面凝胶层的两种镜片材料（Delefilcon A和Verofilcon A）显示出明显更低的细胞损伤测量值。具有大的聚合物筛孔尺寸和高水含量的表面凝胶层被证明是降低接触压力，降低摩擦系数，从而降低剪切应力和细胞损伤的有效方法。与其他镜片相比，具有高水含量表面凝胶层的两种镜片材料（地美洛康A和维罗菲康A）显示出明显更低的细胞损伤测量值。具有大的聚合物筛孔尺寸和高的水含量的表面凝胶层被证明是降低接触压力，降低摩擦系数，从而降低剪切应力和细胞损伤的有效方法。