Scoles Drew, Gray Daniel C, Hunter Jennifer J, Wolfe Robert, Gee Bernard P, Geng Ying, Masella Benjamin D, Libby Richard T, Russell Stephen, Williams David R, Merigan William H
University of Rochester Eye Institute, University of Rochester, Rochester, NY, USA.
BMC Ophthalmol. 2009 Aug 23;9:9. doi: 10.1186/1471-2415-9-9.
Although it has been suggested that alterations of nerve fiber layer vasculature may be involved in the etiology of eye diseases, including glaucoma, it has not been possible to examine this vasculature in-vivo. This report describes a novel imaging method, fluorescence adaptive optics (FAO) scanning laser ophthalmoscopy (SLO), that makes possible for the first time in-vivo imaging of this vasculature in the living macaque, comparing in-vivo and ex-vivo imaging of this vascular bed.
We injected sodium fluorescein intravenously in two macaque monkeys while imaging the retina with an FAO-SLO. An argon laser provided the 488 nm excitation source for fluorescence imaging. Reflectance images, obtained simultaneously with near infrared light, permitted precise surface registration of individual frames of the fluorescence imaging. In-vivo imaging was then compared to ex-vivo confocal microscopy of the same tissue.
Superficial focus (innermost retina) at all depths within the NFL revealed a vasculature with extremely long capillaries, thin walls, little variation in caliber and parallel-linked structure oriented parallel to the NFL axons, typical of the radial peripapillary capillaries (RPCs). However, at a deeper focus beneath the NFL, (toward outer retina) the polygonal pattern typical of the ganglion cell layer (inner) and outer retinal vasculature was seen. These distinguishing patterns were also seen on histological examination of the same retinas. Furthermore, the thickness of the RPC beds and the caliber of individual RPCs determined by imaging closely matched that measured in histological sections.
This robust method demonstrates in-vivo, high-resolution, confocal imaging of the vasculature through the full thickness of the NFL in the living macaque, in precise agreement with histology. FAO provides a new tool to examine possible primary or secondary role of the nerve fiber layer vasculature in retinal vascular disorders and other eye diseases, such as glaucoma.
尽管有人提出神经纤维层血管系统的改变可能参与包括青光眼在内的眼部疾病的病因，但一直无法在体内检查该血管系统。本报告描述了一种新型成像方法，即荧光自适应光学（FAO）扫描激光检眼镜（SLO），它首次实现了在活体猕猴体内对该血管系统进行成像，并比较了该血管床的体内和体外成像。
我们对两只猕猴静脉注射荧光素钠，同时用FAO-SLO对视网膜进行成像。氩激光为荧光成像提供488nm激发源。与近红外光同时获得的反射图像允许对荧光成像的各个帧进行精确的表面配准。然后将体内成像与相同组织的体外共聚焦显微镜检查进行比较。
在神经纤维层内所有深度的浅表焦点（最内层视网膜）显示出一个血管系统，其毛细血管极长、壁薄、管径变化小且平行连接结构与神经纤维层轴突平行，这是放射状视乳头周围毛细血管（RPC）的典型特征。然而，在神经纤维层下方更深的焦点处（朝向视网膜外层），可见神经节细胞层（内层）和视网膜外层血管系统典型的多边形模式。在相同视网膜的组织学检查中也观察到了这些独特模式。此外，通过成像确定的RPC床厚度和单个RPC的管径与组织学切片中测量的结果紧密匹配。
这种可靠的方法在活体猕猴体内实现了对神经纤维层全厚度血管系统的高分辨率共聚焦成像，与组织学结果精确一致。FAO提供了一种新工具，可用于研究神经纤维层血管系统在视网膜血管疾病和其他眼部疾病（如青光眼）中可能的原发性或继发性作用。
