RETINAL NERVE FIBER LAYER REFLECTANCE MECHANISMS

青光眼的诊断和治疗需要敏感的方法 检测和测量视网膜神经纤维的损伤。新开发的 光学评价视网膜神经纤维层的定量方法 (RNFL)承诺提高敏感性和客观性，但更基本 需要知识来解释和改进它们。 这项研究的长期目标是提供一个全面的 RNFL光学性质的定量描述，以及TO 建立其反射率的解剖学基础。 对蟾蜍视网膜的实验表明，RNFL的反射率来自 均匀分布的圆柱形结构。一种新的理论模型 基于神经纤维束的超微结构提示轴突 膜在反射率中占主导地位，但初步实验表明 RNFL反射率的很大一部分来自 微管。该模型预测了膜和微管的机制 在偏振光中应该有不同的表现。 该项目的具体目标是： 1)对大鼠RNFL进行反射测量，以确认发现的属性 在蟾蜍中发生的更普遍，并检验轴突的预测 膜对RNFL反射率起主导作用； 2)用秋水仙碱解聚微管，以检测 假设RNFL的反射率是由 微管； 3)利用偏振光拓宽RNFL的定量描述 反射率和评估膜的相对贡献 微管连接到反射机制；以及 4)定量研究了蟾蜍、大鼠、 以及人体，以便将反射术与解剖学联系起来。 反射实验将使用一种独特的仪器进行， 成像微反射仪，体外制剂和形态 将在相同的组织上进行测量。通过关联 反射仪对RNFL的形态进行了多种反射机理的研究。 此外，所获得的数据将拓宽对 RNFL反射率，并提供了坚实的知识基础 建立青光眼的RNFL评估方法。

The diagnosis and management of glaucoma requires sensitive methods for detecting and measuring damage to retinal nerve fibers. Newly-developed quantitative methods for optically assessing the retinal nerve fiber layer (RNFL) promise to enhance sensitivity and objectivity, but more basic knowledge is needed to interpret and improve them. The long-term objectives of this research are to provide a comprehensive quantitative description of the optical properties of the RNFL, and to establish the anatomical basis for its reflectance. Experiments with toad retina showed that the RNFL reflectance arises from uniformly-distributed cylindrical structures. A new theoretical model based on the ultrastructure of nerve fiber bundles suggests that axonal membranes dominate the reflectance, but preliminary experiments suggest that a substantial fraction of the RNFL reflectance comes from microtubules. The model predicts that membrane and microtubule mechanisms should behave differently in polarized light. The specific aims of this project are to: 1) perform reflectometry of rat RNFL to confirm that properties discovered in toad occur more generally, and to test the prediction that axonal membranes dominate the RNFL reflectance; 2) use colchicine to depolymerize microtubules in order to test the hypothesis that the RNFL reflectance arises from light scattered by microtubules; 3) use polarized light to broaden the quantitative description of the RNFL reflectance and to assess the relative contributions of membranes and microtubules to the reflectance mechanisms; and 4) study quantitatively the ultrastructure of RNFL tissue from toad, rat, and human in order to relate reflectometry to anatomy. Reflectometric experiments will be performed with a unique apparatus, an imaging microreflectometer, on in vitro preparations, and morphological measurements will be obtained on the same tissue. By relating reflectometry to morphology for a variety of RNFL reflectance mechanism. Additionally the data obtained will broaden the quantitative description of the RNFL reflectance and provide a solid foundation of knowledge upon which to develop RNFL assessment methods for glaucoma.