Hammer Martin, Vilser Walthard, Riemer Thomas, Schweitzer Dietrich
University of Jena, Department of Ophthalmology, Jena, Germany.
J Biomed Opt. 2008 Sep-Oct;13(5):054015. doi: 10.1117/1.2976032.
The purpose of this study was to measure the hemoglobin oxygenation in retinal vessels and to evaluate the sensitivity and reproducibility of the measurement. Using a fundus camera equipped with a special dual wavelength transmission filter and a color charge-coupled device camera, two monochromatic fundus images at 548 and 610 nm were recorded simultaneously. The optical densities of retinal vessels for both wavelengths and their ratio, which is known to be proportional to the oxygen saturation, were calculated. From 50-deg images, the used semiautomatic vessel recognition and tracking algorithm recognized and measured vessels of 100 microm or more in diameter. On average, arterial and venous oxygen saturations were measured at 98+/-10.1% and 65+/-11.7%, respectively. For measurements in the same vessel segments from the five images per subject, standard deviations of 2.52% and 3.25% oxygen saturation were found in arteries and veins, respectively. Respiration of 100% oxygen increased the mean arterial and venous oxygen saturation by 2% and 7% respectively. A simple system for noninvasive optical oximetry, consisting of a special filter in a fundus camera and software, was introduced. It is able to measure the oxygen saturation in retinal branch vessels with reproducibility and sensitivity suitable for clinical investigations.
本研究的目的是测量视网膜血管中的血红蛋白氧合情况，并评估该测量方法的敏感性和可重复性。使用配备特殊双波长透射滤光片和彩色电荷耦合器件相机的眼底相机，同时记录548纳米和610纳米处的两幅单色眼底图像。计算两个波长下视网膜血管的光密度及其比值，该比值已知与氧饱和度成正比。利用50度图像，所采用的半自动血管识别和跟踪算法识别并测量直径为100微米或更大的血管。平均而言，动脉和静脉的氧饱和度分别测得为98±10.1%和65±11.7%。对于每个受试者五幅图像中相同血管段的测量，动脉和静脉氧饱和度的标准差分别为2.52%和3.25%。吸入100%氧气使平均动脉和静脉氧饱和度分别增加2%和7%。介绍了一种简单的无创光学血氧测定系统，该系统由眼底相机中的特殊滤光片和软件组成。它能够以适合临床研究的可重复性和敏感性测量视网膜分支血管中的氧饱和度。
