Ang J H, Efron N
Department of Optometry, University of Melbourne, Parkville, Victoria, Australia.
Optom Vis Sci. 1990 Jul;67(7):512-21. doi: 10.1097/00006324-199007000-00009.
Restriction of both oxygen influx to the cornea and carbon dioxide efflux from the cornea by contact lenses results in adverse tissue changes. We measured the extent of hypoxia and hypercapnia at the corneal surface of 10 human volunteers during static, dynamic (blinking), and closed-eye wear of hydrogel and nonhydrogel contact lenses of different gas transmissibilities. During open-eye wear, hypoxia and hypercapnia are lower beneath lenses of higher oxygen and carbon dioxide transmissibilities, respectively (p less than 0.001). Blinking plays a significant role in alleviating corneal hypoxia (p less than 0.05), but not hypercapnia, during lens wear. In the absence of lenses, the gaseous tensions at the anterior corneal surface during eye closure were: pO2 = 37.4 +/- 20.9 mm Hg and pCO2 = 39.3 +/- 3.1 mm Hg. Closed-eye lens wear resulted in greater levels of hypoxia and hypercapnia that were directly correlated with lens transmissibility (p less than 0.001). These data form the basis of models for predicting adverse tissue changes during contact lens wear and suggest prophylactic and therapeutic clinical strategies for alleviating lens-induced hypoxia and hypercapnia.
隐形眼镜对角膜氧气流入和二氧化碳流出的限制会导致不良的组织变化。我们测量了10名人类志愿者在静态、动态（眨眼）以及佩戴不同气体透过率的水凝胶和非水凝胶隐形眼镜闭眼状态下角膜表面的缺氧和高碳酸血症程度。在睁眼佩戴时，分别在氧气透过率较高和二氧化碳透过率较高的镜片下方，缺氧和高碳酸血症程度较低（p小于0.001）。在佩戴镜片期间，眨眼在减轻角膜缺氧方面发挥着重要作用（p小于0.05），但对高碳酸血症无此作用。在不佩戴镜片的情况下，闭眼时角膜前表面的气体张力为：pO2 = 37.4 +/- 20.9毫米汞柱，pCO2 = 39.3 +/- 3.1毫米汞柱。闭眼佩戴镜片会导致更高程度的缺氧和高碳酸血症，且与镜片的透过率直接相关（p小于0.001）。这些数据构成了预测隐形眼镜佩戴期间不良组织变化模型的基础，并提出了减轻镜片引起的缺氧和高碳酸血症的预防性和治疗性临床策略。
