Crittin Mireille, Schmidt Hartmut, Riva Charles E
Institut de Recherche en Ophtalmologie (IRO), Laboratoire d'Optique et de Biophysique, Grand-Champsec 64, CH-1950 Sion, Switzerland.
Klin Monbl Augenheilkd. 2002 Apr;219(4):289-91. doi: 10.1055/s-2002-30648.
Development of a reflectance oximeter to measure non-invasively the changes in oxygen saturation (SO 2 ) in the vessels of the human eye fundus, with the goal of obtaining a better understanding of the retinal circulation in health and disease.
For retinal oximetry, an instrument must image the retina at multiple wavelengths (lambda) and measure the apparent optical density (OD lambda ) of retinal vessels. The new IRO oximeter acquires two-dimensional images of the retina at four different wavelengths simultaneously. The hemoglobin oxygen saturation is calculated using the spectral images at 569 nm (not sensitive to the oxygenation status of hemoglobin) and at 600 nm (sensitive to the oxygenation status).
To test the method, two subjects were asked to breathe first room air and then pure oxygen. During hyperoxia (100 % O 2 breathing), the apparent optical density ratio (OD 600 /OD 569 ) decreases significantly, and consequently, the SO 2 in the veins increases.
The optical density ratio method could be used for relative oxygen saturation measurements, for example, for determining the variation of the SO 2 under various physiological conditions, before and after an intervention or for monitoring retinal diseases such as diabetic retinopathy.
开发一种反射式血氧计，用于无创测量人眼底血管中氧饱和度（SO₂）的变化，目的是更好地了解健康和疾病状态下的视网膜循环。
对于视网膜血氧测定，仪器必须在多个波长（λ）下对视网膜成像，并测量视网膜血管的表观光密度（ODλ）。新型IRO血氧计可同时在四个不同波长下获取视网膜的二维图像。使用569nm（对血红蛋白的氧合状态不敏感）和600nm（对氧合状态敏感）处的光谱图像计算血红蛋白氧饱和度。
为测试该方法，让两名受试者先呼吸室内空气，然后呼吸纯氧。在高氧状态（呼吸100% O₂）下，表观光密度比（OD₆₀₀/OD₅₆₉）显著降低，因此静脉中的SO₂增加。
光密度比法可用于相对氧饱和度测量，例如，用于确定各种生理条件下、干预前后SO₂的变化，或用于监测糖尿病视网膜病变等视网膜疾病。
