RETINAL NERVE FIBER LAYER REFLECTANCE MECHANISMS

描述（由申请人提供）：青光眼的诊断和治疗需要灵敏的方法来检测和测量视网膜神经节细胞及其轴突的损伤。光学评估视网膜神经纤维层（RNFL）的新定量方法已经开始提供比以前的方法更高的灵敏度和客观性，并正在走向常规临床使用。本延续项目的长期目标是：a）提供对RNFL光学特性的全面、定量、基本的了解; B）将这些基本知识转化为对脑胶质瘤损伤临床评估的实际改进。 将使用成像显微偏振仪、扫描激光偏振仪和光学相干断层扫描仪实现以下具体目标： 1)通过表征其物理和生物学特性来识别负责RNFL光学特性的圆柱形结构。RNFL表现为嵌入在双折射板中的近似平行的光散射圆柱体的均匀厚阵列。反射光谱表明两个圆柱形的机制，一个薄的波长和其他厚。将确定圆柱体的身份和RNFL双折射的机制。 2)在体外实验中验证RNFL双折射与神经纤维束结构关系的三个假设。 3)测量和映射人类的RNFL双折射，作为RNFL“组织诊断”的基础。生物荧光是组织的固有特性，直接依赖于RNFL超微结构，并可能提供一种早期检测青光眼神经节细胞结构损伤的方法。

DESCRIPTION (provided by applicant): The diagnosis and management of glaucoma require sensitive methods for detecting and measuring damage to retinal ganglion cells and their axons. New quantitative methods for optically assessing the retinal nerve fiber layer (RNFL) have begun to deliver enhanced sensitivity and objectivity over previous methods and are moving toward routine clinical use. The long-term objectives of this continuation project are a) to provide a comprehensive, quantitative, basic understanding of the optical properties of the RNFL and b) to translate this basic knowledge into practical improvements in clinical assessment of glaucomatous damage. Imaging micropolarimetry, scanning laser polarimetry and optical coherence tomography will be used to pursue the following Specific Aims: 1) Identify the cylindrical structures responsible for the optical properties of the RNFL by characterizing their physical and biological properties. The RNFL behaves as a uniform thick array of approximately parallel light scattering cylinders embedded in a birefringent slab. Reflectance spectra suggest two cylindrical mechanisms, one thin relative to the wavelength and the other thicker. The identities of the cylinders and the mechanism for RNFL birefringence will be determined. 2) Test in vitro three hypotheses about the relation between RNFL birefringence and the structure of nerve fiber bundles. 3) Measure and map RNFL birefringence in humans as a basis for "tissue diagnosis" of the RNFL. Birefringence is an intrinsic property of the tissue, depends directly on RNFL ultrastructure, and may provide a means of early detection of structural damage to ganglion cells in glaucoma.