Optical Imaging of Retinal Blood Circulation

视网膜血流动力学的评价是眼科诊断的重要课题，也是眼科学研究的难点之一。视网膜为中枢神经系统以及传入和传出中枢神经系统脉管系统提供直接光学通路。这种独特的功能为几代眼科医生提供了评估多系统疾病的能力，而无需侵入性诊断测试，使用直接和间接检眼镜和裂隙灯生物显微镜检查。然而，这些技术不能直接量化视网膜血流速度，也不能检测预测最终显著发病率的临床前改变。预防医学的趋势规定了一种更灵敏的技术，以可靠地量化视网膜血流动力学的细微变化。这个第二阶段项目的主要目标是测试所提出的成像技术用于测量人类视网膜速度的可行性。第二阶段的具体目标包括（1）开发先进的原型，（2）改进算法，（3）进行临床研究，（4）调查准确性和实用性，以及（5）检查商业应用问题。所提出的成像方法采用动态事件的空间平均，仅需要一个图像用于血液速度计算。它允许近实时地获取全视野视网膜图像。短曝光时间减少了运动伪影的影响。这项新技术有可能改善患者的眼部管理。散斑成像仪可以以激光多普勒设备的一小部分成本并入眼底照相机中。一种非侵入性的实时视网膜成像仪允许医生记录和跟踪患者的视网膜血流动力学，以检测眼部疾病的早期迹象。

The evaluation of retinal hemodynamics is an import diagnostic subject and has been one of the most difficult challenges in ophthalmology. The retina provides direct optical access to both the central nervous system and afferent and efferent central nervous system vasculature. This unique feature has provided generations of ophthalmologists with the ability to evaluate multi-system diseases without invasive diagnostic testing, using direct and indirect ophthalmoscopy, and slit lamp biomicroscope examination. These techniques, however, cannot directly quantify retinal blood velocity, nor do they detect preclinical alterations predictive of eventual significant morbidity. The trend toward preventive medicine prescribes a more sensitive technique to reliably quantify subtle changes in retinal hemodynamics. The main objective of this Phase II project is to test the feasibility of the proposed imaging technique for the measurement of human retinal velocities. Specific aims of Phase II include (1) to develop an advanced prototype, (2) to improve algorithms, (3) to conduct clinical research, (4) to investigate accuracy and utility, and (5) to examine commercial application issues. The proposed imaging method employs spatial averaging of the dynamic events, only one image is needed for blood velocity calculations. It allows acquiring of full-field retinal images in near realtime. The short exposure time reduces the effects of motion artifacts. This new technology has the potential to improve ocular management of patients. The speckle imager can be incorporated in a fundus camera at a fraction of the cost of a laser Doppler device. A noninvasive, realtime retinal imager allows the physicians to record and keep track of patients' retinal hemodynamics to detect early signs of ocular disorders.