CORNEAL EFFECTS OF CONTACT LENS ACIDOSIS

本项目研究隐形眼镜诱导的间质 酸中毒引起角膜结构和功能的永久性变化。 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，减少角膜水合作用 对照组，并减慢诱导水肿后的角膜恢复。这些结果 也表明隐形眼镜引起的基质酸中毒可能改变角膜 因此，深入研究pH值是非常重要的。 由CL磨损引起的介导效应。为了研究这些影响， 必须找到临界透镜氧透过率（Dk/L）， 在戴隐形眼镜时避免基质酸中毒 条件在确定了这个临界Dk/L值之后，我们现在建议： 研究角膜变化的发展和可逆性， 长期配戴隐形透镜引起的角膜酸中毒。的 实验设计提供了2个延长磨损组， 除了一种透镜类型降低角膜pH值， 其他透镜类型不影响角膜pH值。 角膜结构和功能将在2-1/2年的时间内完成。透镜- 配戴阶段之后是3个月的时间段，在此期间配戴接触透镜， 停止了。使用这种模式，将有可能评估 长期配戴导致的角膜pH值降低对 接触透镜引起的角膜病变的发展和可逆性。的 从这项研究中获得的信息将进一步加深我们对 接触透镜角膜并发症的性质和病因 佩戴，改进现有接触透镜治疗策略，开发 消除基质中存在的透镜配戴条件的指南 酸中毒可能使接触透镜的患者处于“危险”中，并且 提供了细胞外pH值变化对 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.