Visualization of retinal ganglion cells ex vivo using full-field optical coherence tomography

在活体猪眼杯中评价了使用卤素灯的全支撑光学相干断层扫描（FF-OCT）。比较了不同光源带宽、视场和CCD像素数对视网膜成像性能的影响，从临床角度提出了一种最佳的视网膜细胞结构成像装置，即120 nm带宽、850 μm × 850 μm、500 × 500像素的CCD。120 nm的带宽提供了2μm的轴向分辨率。在这种情况下，视网膜神经节细胞被描绘为圆形低反射点。此外，在视网膜神经纤维层中描绘了神经纤维束。其次，我们尝试在连续OCT切片上使用体绘制技术重建三维图像。视网膜神经节细胞表现为低反射球。此外，在视网膜神经纤维层中可见纤维样结构。视网膜神经节细胞分布在三维空间中。因此，不可能通过使用单个切片来计数视网膜神经节细胞的数量。视网膜神经节细胞的三维可视化允许计数它们的数量。目前的OCT技术允许测量视网膜神经纤维层的厚度。然而，视网膜神经纤维层厚度的测量具有也测量视网膜神经纤维束丢失的空间的风险。通过FF-OCT对神经纤维束的可视化允许仅测量神经纤维束的实际量。因此，FF-OCT在我们的设置打开了一个新的途径来研究视网膜神经节细胞和神经纤维束的青光眼损害。如果这项技术在活体人眼中发挥作用，将在青光眼诊断方面取得划时代的进展。我们的研究结果为FF-OCT技术的临床应用提供了证据。

Full-held optical coherence tomography (FF-OCT) using Halogen lamp was evaluated a vivo in pig eye cups. Effects of varying band widths of light source, fields of view and numbers of CCD pixel on imaging performance of retina were compared_ We fund a best setting composing 120 nm band width, 850 μm x850 μm, and 500 x 500 pixels of CCD for imaging retinal cellular structures from clinical point of view. The 120 nm band width gives a 2μm of axial resolution. In this setting, retinal ganglion cells were depicted as round hyporeflective spots. In addition, nerve fiber bindles were depicted in the retinal nerve fiber layer. Next, we tried to reconstruct 3-dimensional images by using volume rendering technique on serial OCT sections. The retinal ganglion cells were depicted hyporeflective balls. In addition, fiber-like structures were visualized in the retinal nerve fiber layer. Retinal ganglion cells are distributed in the 3-dimensional space. Therefore, it is impossible to count the number of retinal ganglion cells by using single sections. The 3-dimensional visualization of retinal ganglion cells allow for counting their numbers. The current OCT technology allows measurement of thickness of retinal nerve fiber layer. However, measurement of retinal nerve fiber layer thickness has the risk that the space in which retinal nerve fiber bundles are lost are also measured. Visualization of nerve fiber bundles by FF-OCT allows measurement of only the actual amount of nerve fiber bundles. Thus, FF-OCT at our setting opens a new avenue to study glaucomatous damage on retinal ganglion cells and nerve fiber bundles. If this technology works in live human eyes, it would make an epoch-making progress in the diagnosis of glaucoma. Our results give evidence supporting the motivation that clinical application of FF-OCT technology.