Y Lin Ken, Mosaed Sameh
Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, USA.
J Ophthalmic Vis Res. 2019 Jul 18;14(3):275-284. doi: 10.18502/jovr.v14i3.4783. eCollection 2019 Jul-Sep.
There is a growing interest in targeting minimally invasive surgery devices to the aqueous outflow system to optimize treatment outcomes. However, methods to visualize functioning, large-caliber aqueous and episcleral veins are lacking. This pilot study establishes an system to evaluate the use of a confocal laser microendoscope to noninvasively image episcleral vessels and quantify regional flow variation along the limbal circumference.
A fiber-optic confocal laser endomicroscopy (CLE) system with lateral and axial resolution of 3.5 m and 15 m, respectively, was used on three porcine and four human eyes. Diluted fluorescein (0.04%) was injected into eyes kept under constant infusion. The microprobe was applied to the sclera 1 mm behind the limbus to acquire real-time video. Image acquisition was performed at 15-degree intervals along the limbal circumference to quantify regional flow variation in human eyes.
Vascular structures were visualized in whole human eyes without processing. Schlemm's canal was visualized only after a scleral flap was created. Fluorescent signal intensity and vessel diameter variation were observed along the limbal circumference, with the inferior quadrant having a statistically higher fluorescein signal compared to the other quadrants in human eyes ( < 0.05).
This study demonstrates for the first time that the fiber-optic CLE platform can visualize the episcleral vasculature with high resolution with minimal tissue manipulation. Intravascular signal intensities and vessel diameters were acquired in real-time; such information can help select target areas for minimally invasive glaucoma surgery (MIGS) to achieve greater intraocular pressure reduction.
将微创手术设备靶向至房水流出系统以优化治疗效果，这一领域的关注度日益增加。然而，目前缺乏可视化功能性大口径房水静脉和巩膜上静脉的方法。本前瞻性研究建立了一个系统，用于评估共聚焦激光显微内镜在无创成像巩膜上血管以及量化沿角膜缘圆周的局部血流变化方面的应用。
使用侧向和轴向分辨率分别为3.5微米和15微米的光纤共聚焦激光内镜系统（CLE），对三只猪眼和四只人眼进行检查。将稀释的荧光素（0.04%）注入持续灌注的眼中。将微型探头应用于角膜缘后1毫米处的巩膜，以获取实时视频。沿角膜缘圆周以15度间隔进行图像采集，以量化人眼中的局部血流变化。
未经处理的整个人眼中均可观察到血管结构。仅在制作巩膜瓣后才观察到施莱姆管。沿角膜缘圆周观察到荧光信号强度和血管直径变化，人眼中下象限的荧光素信号在统计学上高于其他象限（P<0.05）。
本研究首次证明，光纤CLE平台能够以高分辨率可视化巩膜上血管系统，且组织操作最少。实时获取血管内信号强度和血管直径；这些信息有助于选择微创青光眼手术（MIGS）的目标区域，以实现更大程度的眼压降低。
