Felder Anthony E, Wanek Justin, Blair Norman P, Shahidi Mahnaz
Invest Ophthalmol Vis Sci. 2015 Oct;56(11):6633-7. doi: 10.1167/iovs.15-17321.
Light flicker has been shown to stimulate retinal neural activity, increase blood flow, and alter inner retinal oxygen metabolism (MO2) and delivery (DO2). The purpose of the study was to determine the change in MO2 relative to DO2 due to light flicker stimulation in humans, as assessed by the inner retinal oxygen extraction fraction (OEF).
An optical imaging system, based on a modified slit lamp biomicroscope, was developed for simultaneous measurements of retinal vascular diameter (D) and oxygen saturation (SO2). Retinal images were acquired in 20 healthy subjects before and during light flicker stimulation. Arterial and venous D (DA and DV) and SO2 (SO2A and SO2V) were quantified within a circumpapillary region. Oxygen extraction fraction was defined as the ratio of MO2 to DO2 and was calculated as (SO2A - SO2V)/SO2A. Reproducibility of measurements was assessed.
Coefficients of variation and intraclass correlation coefficients of repeated measurements were <5% and ≥0.83, respectively. During light flicker stimulation, DA, DV , and SO2V significantly increased (P ≤ 0.004). Oxygen extraction fraction was 0.37 ± 0.08 before light flicker and significantly decreased to 0.31 ± 0.07 during light flicker (P = 0.001).
Oxygen extraction fraction before and during light flicker stimulation is reported in human subjects for the first time. Oxygen extraction fraction decreased during light flicker stimulation, indicating the change in DO2 exceeded that of MO2. This technology is potentially useful for the detection of changes in OEF response to light flicker in physiological and pathological retinal conditions.
已有研究表明，光闪烁可刺激视网膜神经活动、增加血流量并改变视网膜内层的氧代谢（MO2）和输送（DO2）。本研究的目的是通过视网膜内层氧摄取分数（OEF）评估，确定人类在光闪烁刺激下MO2相对于DO2的变化。
开发了一种基于改良裂隙灯生物显微镜的光学成像系统，用于同时测量视网膜血管直径（D）和氧饱和度（SO2）。在20名健康受试者中，于光闪烁刺激前和刺激期间采集视网膜图像。在视乳头周围区域定量测定动脉和静脉的D（DA和DV）以及SO2（SO2A和SO2V）。氧摄取分数定义为MO2与DO2的比值，计算方法为（SO2A - SO2V）/SO2A。评估测量的可重复性。
重复测量的变异系数和组内相关系数分别<5%和≥0.83。在光闪烁刺激期间，DA、DV和SO2V显著增加（P≤0.004）。光闪烁前氧摄取分数为0.37±0.08，在光闪烁期间显著降至0.31±0.07（P = 0.001）。
首次报道了人类受试者在光闪烁刺激前后的氧摄取分数。在光闪烁刺激期间氧摄取分数降低，表明DO2的变化超过了MO2。该技术可能有助于检测生理和病理视网膜状态下OEF对光闪烁反应的变化。
