Zhou Q, Knighton R W
Appl Opt. 1997 Apr 1;36(10):2273-85. doi: 10.1364/ao.36.002273.
The retinal nerve fiber layer (RNFL) comprises bundles of unmyelinated axons that run across the surface of the retina. The cylindrical organelles of the RNFL (axonal membranes, microtubules, neurofilaments, and mitochondria) as seen by electron microscopy were modeled as parallel cylindrical arrays in order to gain insight into their optical properties. Arrays of thin fibrils were used to represent organelles that are thin relative to wavelength, and the model took into account interference effects that may arise from spatial order. Angular and spectral light-scattering functions were calculated for the backscattering hemisphere. Scattering was much larger from axonal membranes than from microtubules or neurofilaments. Spectra from 400 to 700 nm show that scattering increases at shorter wavelengths for both axonal membranes and microtubules. At 560 nm, scattering from mitochondria modeled as thick cylinders was approximately the same as that from microtubules but showed little wavelength dependence. The model reveals differences in backscattered polarization ratios that may permit experimental discrimination between microtubule and membrane mechanisms for the RNFL reflectance. Calculated backscattering exceeds measured values by at least 1 order of magnitude, but calculated form birefringence for microtubule arrays is approximately the same as measured birefringence.
视网膜神经纤维层（RNFL）由横穿视网膜表面的无髓鞘轴突束组成。通过电子显微镜观察到的RNFL的圆柱形细胞器（轴突膜、微管、神经丝和线粒体）被建模为平行圆柱阵列，以便深入了解它们的光学特性。细纤维阵列被用来表示相对于波长较细的细胞器，该模型考虑了可能由空间顺序引起的干涉效应。计算了后向散射半球的角度和光谱光散射函数。轴突膜的散射比微管或神经丝的散射大得多。400至700纳米的光谱表明，轴突膜和微管在较短波长下的散射都会增加。在560纳米处，建模为粗圆柱体的线粒体的散射与微管的散射大致相同，但几乎没有波长依赖性。该模型揭示了后向散射偏振比的差异，这可能允许通过实验区分RNFL反射率的微管和膜机制。计算出的后向散射比测量值至少高出1个数量级，但计算出的微管阵列双折射与测量的双折射大致相同。
