Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, Missouri, USA.
Br J Ophthalmol. 2011 Jan;95(1):118-22. doi: 10.1136/bjo.2010.186064. Epub 2010 Sep 23.
Alterations in intraocular oxygen levels are important contributors to, or indications of, ocular disease. Polarographic electrodes and fibre-optic sensors (optodes) have been used to measure oxygen and to map the distribution of oxygen in animal models and in human eyes. A recent study reported the use of a commercial electrode to compare oxygen distribution in the vitreous of patients undergoing vitrectomy related to central retinal vein occlusion, macular hole or preretinal membrane. The results of this study were at variance with previous measures of oxygen distribution in the human vitreous using polarographic or optical sensors. To resolve this discrepancy, the present study compared measurements made in vitro or in animal eyes, using the electrode employed in the previous study or a fibre-optic sensor of a different design.
Comparative in vitro and in vivo measurements.
In vitro, the two devices reported similar levels of oxygen, although the electrode consistently detected levels above the calculated values. In rabbit eyes, the electrode had a slow response time and was unable to detect oxygen gradients that were readily measured by the smaller optode. When the electrode was inserted into an eye of similar size to the human eye, the reference thermistor measured the temperature outside the eye, not in the vitreous.
The design of the electrode used in the previous study makes it unsuitable for measurements of oxygen distribution in the eye.
眼内氧水平的改变是眼部疾病的重要诱因或指示。极谱电极和光纤传感器（光探头）已被用于测量动物模型和人眼中的氧含量，并绘制氧的分布图谱。最近的一项研究报告了使用商业电极来比较与视网膜中央静脉阻塞、黄斑裂孔或视网膜前膜相关的玻璃体切割术中患者的玻璃体中氧的分布。该研究的结果与先前使用极谱或光学传感器测量人玻璃体中氧分布的结果不一致。为了解决这一差异，本研究比较了使用先前研究中使用的电极或不同设计的光纤传感器在体外或动物眼中进行的测量。
体外和体内比较测量。
在体外，两种设备报告的氧水平相似，尽管电极始终检测到高于计算值的水平。在兔眼中，电极的响应时间较慢，无法检测到较小的光探头可以轻松测量的氧梯度。当将电极插入与人眼大小相似的眼睛中时，参考热敏电阻测量的是眼睛外部的温度，而不是玻璃体中的温度。
先前研究中使用的电极设计使其不适合测量眼睛中的氧分布。
