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首页> 外文学位 >Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling.
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Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling.

机译：氧气通过软性角膜接触镜和角膜的传输：晶状体表征和代谢建模。

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The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs).; Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs.; The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea.; Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate.; Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A new parameter "Oxygen Deficiency Factor" (ODF) is defined to quantify oxygen deficiency in local regions of the cornea. We use this concept to determine the minimum required contact-lens oxygen transmissibility, Dk/L = 150 Barrer/cm, to avoid hypoxia-induced corneal physiologic complications.
机译：人角膜需要氧气来维持对其正常功能至关重要的代谢过程。外部环境对角膜氧气供应的任何限制（例如，佩戴低氧渗透性隐形眼镜）都可能导致缺氧，这可能导致角膜浮肿（肿胀），角膜缘充血，新血管形成和角膜酸中毒。角膜需要足够的氧气是研究和开发超透射软隐形眼镜（SCL）的主要动力。当前，没有用于测量超透射性有机硅-水凝胶SCL的透氧性（Dk）的标准技术。在这项工作中，设计，构建并运行了基于电化学的极谱仪，以测量超透射SCL中的氧气渗透率。与需要一定范围的透镜厚度来确定SCL的氧气渗透率的常规方法不同，此设备仅需要单个透镜厚度。单透镜渗透仪提供了一种可靠，高效且经济的工具，可用于测量商业超透射SCL的氧气渗透率。单透镜渗透仪不仅测量乘积Dk，而且经过修改后，它还分别测量超透射性SCL中氧气的扩散率D和溶解度k。这些特性对于设计更好的镜片材料至关重要，以确保向角膜提供足够的氧气。角膜接触镜引起的缺氧，糖尿病，外科手术和药物治疗等疾病会影响角膜中氧的代谢，因此，估算体内角膜耗氧率对于衡量角膜的充足氧气供应至关重要。因此，我们为角膜接触镜系统开发了一种非稳态反应扩散模型，以确定体内人角膜耗氧率。最后，开发了一种代谢模型来确定隐形眼镜的氧气透过率（Dk / L）与角膜缺氧之间的关系。定义新参数“缺氧因子”（ODF）以量化角膜局部区域的缺氧。我们使用此概念来确定所需的最低隐形眼镜氧气透过率，Dk / L = 150 Barrer / cm，以避免缺氧引起的角膜生理并发症。

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