Benjamin W J, Ruben C M
School of Optometry, University of Alabama at Birmingham 35294-0010, USA.
J Am Optom Assoc. 1995 Jul;66(7):423-8.
Oxygen depletion of the superior and central cornea in response to standard conditions is of clinical interest because of pathological conditions, usually resulting from the hypoxia of contact lens wear, that affect these areas. A study was designed to determine if there are differences in oxygen depletion at these two sites.
Oxygen depletion times from a standard reservoir following corneal exposure to three different oxygenated environments (20.9%, 5%, and 0% oxygen) were assessed micropolarographically at central, superior, and inferior corneal surface positions on both corneas of six healthy young adult human subjects.
Based on 48 measurements for each corneal position at each oxygen percentage (432 total measurements), the superior cornea 1.0 mm from the limbus was found to have longer oxygen depletion times (slower oxygen uptake rates) than the central or inferior corneal locations. The differences reduced to nearly zero during the course of the initial 1.5-day testing procedure, but were re-established months later when testing was resumed.
There is a small reversible increase in superior corneal oxygen depletion time (a decrease of the oxygen uptake rate) due to the chronic hypoxia that results from the presence of an overlying superior eyelid or other physiological factors.
由于通常由隐形眼镜佩戴导致的缺氧引起的病理状况会影响角膜的上部和中央区域，因此研究标准条件下这些区域的角膜氧耗竭具有临床意义。本研究旨在确定这两个部位的氧耗竭是否存在差异。
对6名健康年轻成年受试者的双眼角膜的中央、上部和下部表面位置进行微极谱法评估，测量角膜暴露于三种不同氧环境（20.9%、5%和0%氧气）后，标准储液器中的氧耗竭时间。
在每个氧含量水平下，每个角膜位置进行48次测量（共432次测量），结果发现，距离角膜缘1.0毫米处的上部角膜的氧耗竭时间比中央或下部角膜位置更长（氧摄取速率更慢）。在最初1.5天的测试过程中，差异降至几乎为零，但在数月后恢复测试时差异又重新出现。
由于上睑覆盖或其他生理因素导致的慢性缺氧，上部角膜的氧耗竭时间会有小幅可逆增加（氧摄取速率降低）。
