CORNEAL EFFECTS OF CONTACT LENS ACIDOSIS

这个项目检验了隐形眼镜诱导基质的假说 酸中毒会导致角膜结构和功能的永久性改变。 现已完成的研究提供了初步证据 角膜酸中毒改变细胞形态，减少角膜水化 控制，并减缓角膜在诱导水肿后的恢复。这些结果 也提示隐形眼镜引起的基质酸中毒可能改变角膜 完整性，因此，重要的是深入探讨pH值- CL磨损产生的中介效应。为了研究这些影响，它是 确定临界透氧率(DK/L)的必要性 戴隐形眼镜避免间质酸中毒 条件。在确定了这个关键的DK/L值之后，我们现在建议 研究由此导致的角膜变化的发展和可逆性 由于长时间佩戴隐形眼镜而导致的角膜酸中毒。这个 实验设计提供了两组相同的延长磨损组 配戴特点，除了一种镜片类型降低角膜pH值，而 另一种镜片类型不影响角膜pH值。定期评估 角膜结构和功能将在两年半内完成。镜头- 配戴阶段，之后是3个月的隐形眼镜配戴期 停产。使用此范例，将有可能评估 长时间佩戴引起的角膜pH值降低对角膜的影响 隐形眼镜所致角膜病变的发展及可逆性。这个 从这项研究中获得的信息将进一步加深我们对 隐形眼镜致角膜并发症的性质和病因 佩戴，改进目前的隐形眼镜治疗策略，发展 消除配戴镜片的指南，其中基质 酸中毒可能会将隐形眼镜患者置于危险之中，以及 提供定量数据，说明细胞外pH变化对 角膜结构和功能。

This project examines the hypothesis that contact-lens-induced stromal acidosis causes permanent changes in corneal structure and function. Studies have now been completed which provide preliminary evidence that corneal acidosis alters cell morphology, reduces corneal hydration control, and slows corneal recovery after induced edema. These results also suggest that contact-lens-induced stromal acidosis may alter corneal integrity, and therefore it is important to explore in some depth the pH- mediated effects that result from CL wear. To study these effects, it was necessary to find the critical lens oxygen transmissibility (Dk/L) for avoiding stromal acidosis under closed-eye contact-lens-wearing conditions. Having determined this critical Dk/L value, we now propose to study the development and reversibility of corneal changes that result from corneal acidosis induced by extended contact lens wear. The experimental design provides for 2 extended-wear groups with identical fitting characteristics except that one lens type lowers corneal pH while the other lens type does not affect corneal pH. Regular assessments of corneal structure and function will be made during a 2-1/2 yr. lens- wearing phase followed by a 3-month period in which contact lens wear is discontinued. Using this paradigm, it will be possible to assess the impact of reduced corneal pH resulting from extended wear on the development and reversibility of contact lens induced keratopathies. The information obtained from this study will further our understanding of the nature and etiology of corneal complications resulting from contact lens wear, improve present contact lens treatment strategies, develop guidelines for elimination of those lens wearing conditions where stromal acidosis is likely to place the contact lens patient "at risk," and provide quantitative data on the effects of changes in extracellular pH on corneal structure and function.