Development of an istrument evaluating re tinal circulation in vivo.

安装眼底照相机，将氩蓝激光投射到眼底出现激光散斑图案处。将散斑图案成像到图像传感器（100*100像素）上，从该图像传感器计算归一化模糊值（NB）作为组织血流速度的定量指标。在兔实验中，当诱导眼内压逐步增加时，从视网膜获得的NB与通过微球方法在同一只眼睛中测定的血流速率表现出良好且显著的相关性。这些结果表明，NB值反映了视网膜的循环状态和非接触和非侵入性测量视网膜血流动力学在活体眼睛是可能的。对该装置进行了改进，使其能测量视网膜大静脉血流速度，测得人视网膜大静脉血流速度平均为1.5- 2.0cm/sec，与其它方法测得的结果一致，并应用该装置评价了全身性钙拮抗剂对视网膜外周循环的影响。尼伐地平、普拉地平、司莫噻嗪和尼卡地平均能增加视网膜组织血流速度，但司莫噻嗪的作用最为显著。此外，口服semothiazil后用微球法测定的视网膜血流速率的增加与口服semothiazil后NB值的增加一致，这进一步保证了激光散斑方法的有效性。本研究证实了该装置的有效性，以及口服钙拮抗剂用于与血流减少相关的视网膜疾病的可能性。

A fundus camera was installed with argon blue laser which was projected onto the ocular fundus where laser speckle patter appears. Speckle pattern was imaged onto an image sensor (100*100 pixels) from which normalized blur value (NB) was calculated as a quantitative index of tissue blood velocity. In rabbit experiments, NB obtained from the retina showed a good and significant correlation with the blood flow rate determined by the microsphere method in the same eye, when stepwise increase in the intraocular pressure was induced. These results indicated that NB value reflects the cirdulation status of the retina and non-contact and noninvasive measurement of retinal hemodynamics is possible in living eyes using the apparatus constructed. Further, the apparatus was improved so that it can measure the blood velocity in large retinal veins and the blood velocity in the large retinal veins in humans was found to average 1.5-2.0 cm/sec, which agreed well with the value obtained by other methods.Using the apparatus constructed, effect of systemic calcium antagonists on retinal peripheral circulation was evaluated. Nilvadipine, pranidipine, semothiazil and nicardipine were found to increase the retinal tissue blood velocity, but the effect of semothiazil appeared to be most prominent. Further, increase in the retinal blood flow rate determined with the microsphere method after oral semothiazil agreed well with increase in the NB value after oral semothiazil, which further warrants the validity of the laser speckle methodology. The present study demonstrated the usefulness of the apparatus constructed here and possibility that oral calcium antagonist can by used in retinal disorders associated with reduced blood flow.