Measurement of Absolute Retinal Blood Flow Using a Laser Doppler Velocimeter Combined with Adaptive Optics

Data set of measurements related to the following:

Purpose: Development and validation of an absolute laser Doppler velocimeter (LDV) based on an adaptive optical fundus camera which provides simultaneously high definition images of the fundus vessels and absolute maximal red blood cells (RBCs) velocity in order to calculate the absolute retinal blood flow.

Methods: This new absolute laser Doppler velocimeter is combined with the adaptive optics fundus camera (rtx1, Imagine Eyes©,Orsay, France) outside its optical wavefront correction path. A 4 seconds recording includes 40 images, each synchronized with two Doppler shift power spectra. Image analysis provides the vessel diameter close to the probing beam and the velocity of the RBCs in the vessels are extracted from the Doppler spectral analysis. Combination of those values gives an average of the absolute retinal blood flow. An in vitro experiment consisting of latex microspheres flowing in water through a glass-capillary to simulate a blood vessel and in vivo measurements on six healthy human retinal venous junctions were done to assess the device.

Results: In the in vitro experiment, the calculated flow varied between 1.75 μl/min and 25.9 μl/min and was highly correlated (r2 = 0.995) with the imposed flow by a syringe pump. In the in vivo experiment, the error between the flow in the parent vessel and the sum of the flow in the daughter vessels was between −25% and 17% (mean±sd −2 ± 17%). Retinal blood flow in the main temporal retinal veins of healthy subjects varied between 1.3 μL/min and 28.7 μL/min

Conclusion: This adaptive optics LDV prototype (aoLDV) allows the measurement of absolute retinal blood flow derived from the retinal vessel diameter and the maximum RBCs velocity in that vessel.

本数据集包含与以下内容相关的测量数据：

研究目的：开发并验证一款基于自适应光学眼底相机（adaptive optical fundus camera）的绝对激光多普勒测速仪（laser Doppler velocimeter, LDV），该设备可同时采集眼底血管的高清图像，并获取红细胞（red blood cells, RBC）的绝对最大速度，以此计算视网膜绝对血流量。

研究方法：将这款新型绝对激光多普勒测速仪集成于自适应光学眼底相机（rtx1，Imagine Eyes©，法国奥赛）的光学波前校正光路之外。单次4秒的记录可采集40幅图像，每幅图像均与两组多普勒频移功率谱同步。通过图像分析可获取探测光束附近的血管直径，同时从多普勒频谱分析中提取血管内红细胞的速度。结合上述两项数值，可计算得到视网膜绝对血流量的平均值。为评估该设备性能，本研究开展了两类实验：其一为体外实验，以乳胶微球在水中流经玻璃毛细管模拟血管；其二为体内实验，对6名健康受试者的视网膜静脉汇合处进行测量。

实验结果：体外实验中，计算所得血流量介于1.75 μl/min至25.9 μl/min之间，与注射泵设定的灌注流量具有极高相关性（决定系数r²=0.995）。体内实验中，主干血管血流量与分支血管血流量总和之间的误差范围为-25%至17%（平均值±标准差：-2 ±17%）。健康受试者颞侧主要视网膜静脉的血流量介于1.3 μL/min至28.7 μL/min之间。

研究结论：这款自适应光学LDV原型机（adaptive optics LDV, aoLDV）可通过视网膜血管直径与该血管内红细胞最大速度，实现视网膜绝对血流量的精准测量。