NONCONTACT, 2-DIMENSIONAL MEASUREMENT OF TISSUE CIRCULATION IN CHOROID AND OPTIC-NERVE HEAD USING LASER SPECKLE PHENOMENON
NONCONTACT, 2-DIMENSIONAL MEASUREMENT OF TISSUE CIRCULATION IN CHOROID AND OPTIC-NERVE HEAD USING LASER SPECKLE PHENOMENON
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DOI：
10.1016/s0014-4835(05)80094-6
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发表时间：
1995-04-01
影响因子：
3.4
通讯作者：
FUJII, H
中科院分区：
文献类型：
--
作者：
TAMAKI, Y;ARAIE, M;FUJII, H
利用激光散斑现象对脉络膜和视神经头（ONH）的组织循环进行非接触、二维分析。用二极管激光光斑照射眼底，用图像传感器检测其图像散斑。计算散斑强度平均值（I-mean）与连续扫描的散斑强度之差，并将I-mean与该差值之比定义为归一化模糊值（NB），这是血流速度的定量指标。结果显示在彩色图形显示器上，显示测量场中网元电平的二维变化。在家兔实验中，利用该仪器研究了NE测量结果与目前采用微球法测定的脉络膜血的关系，戊巴比妥致死注射后无可见表面血管的ONH组织中NE与眼灌注压（OPP）的关系，以及眼内压（IOP）对脉络膜或ONH中NB的影响。通过测量眼压来逐步降低OPP。静脉注射戊巴比妥致死后，脉络膜平均NB （NE(av)）随OPP降低的相对下降与微球技术测定的血流速率的相对变化具有显著相关性（r = 0.60, P < 0.001）， ONH中的NBav与OPP有良好的相关性（r = 0.98, P < 0001）。当OPP高于40 mmHg时，ONR内NE（av）受OPP变化的影响不大，而当OPP低于40 mmHg时，ONR内NE（av）随OPP的降低而降低，这些结果表明，使用本仪器可以在活体眼中无创地研究各种情况下脉络膜或ONH内的血流速度。
A new apparatus has been developed using the laser speckle phenomenon for non-contact, two-dimensional analysis of tissue circulation in the choroid and optic nerve head (ONH). The fundus was illuminated by a diode laser spot and its image speckle was detected by an image sensor. The difference between the average of the speckle intensity (I-mean) and the speckle intensity for successive scannings was calculated, and the ratio of I-mean to this difference was defined as normalized blur (NB), which is a quantitative index of blood velocity. The results were displayed on color graphic monitors showing the two-dimensional variation of the NE level in the measurement field. In the rabbit, this apparatus was used to study the relationship between the results of NE measurement and the choroidal blood now determined by the microsphere technique, the relationship between NE obtained from the ONH tissue free of Visible surface vessels and the ocular perfusion pressure (OPP) after a lethal injection of pentobarital, and the effect of intraocular pressure (IOP) on the NB in the choroid or in the ONH. A stepwise reduction in the OPP was introduced by elevating the IOP manometrically. The relative decrease in the average NB over the field measured, NE(av), in the choroid with the reduction in OPP showed a significant correlation with the relative change in the blood flow rate determined using the microsphere technique (r = 0.60, P < 0.001), NBav in the ONH had a good correlation with the OPP after a lethal injection of pentobarbital (r = 0.98, P < 0001). NE(av) in the choroid decreased with reduction in the OPP. Although NE(av) in the ONH was little affected by OPP change when OPP was above 40 mmHg, at OPP levels below 40 mmHg, NE(av) in the ONR decreased along with a reduction in the OPP. These results suggest that by using the present apparatus, the blood velocity in the choroid or ONH under various conditions can be studied non-invasively in the living eye.