Department of Ophthalmology, University of Würzburg, Würzburg, Germany.
Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
PLoS One. 2020 May 18;15(5):e0232833. doi: 10.1371/journal.pone.0232833. eCollection 2020.
The risk for glaucoma is driven by the microanatomy and function of the anterior segment. We performed a computation-intense, high-resolution, full-thickness ribbon-scanning confocal microscopy (RSCM) of the outflow tract of two human eyes. We hypothesized this would reveal important species differences when compared to existing data of porcine eyes, an animal that does not spontaneously develop glaucoma.
After perfusing two human octogenarian eyes with lectin-fluorophore conjugate and optical clearance with benzyl alcohol benzyl benzoate (BABB), anterior segments were scanned by RSCM and reconstructed in 3D for whole-specimen rendering. Morphometric analyses of the outflow tract were performed for the trabecular meshwork (TM), limbal, and perilimbal outflow structures and compared to existing porcine data.
RSCM provided high-resolution data for IMARIS-based surface reconstruction of outflow tract structures in 3D. Different from porcine eyes with an abundance of highly interconnected, narrow, and short collector channels (CCs), human eyes demonstrated fewer CCs which had a 1.5x greater cross-sectional area (CSA) and 2.6x greater length. Proximal CC openings at the level of Schlemm's canal (SC) had a 1.3x larger CSA than distal openings into the scleral vascular plexus (SVP). CCs were 10.2x smaller in volume than the receiving SVP vessels. Axenfeld loops, projections of the long ciliary nerve, were also visualized.
In this high-resolution, volumetric RSCM analysis, human eyes had far fewer outflow tract vessels than porcine eyes. Human CCs spanned several clock-hours and were larger than in porcine eyes. These species differences may point to factors downstream of the TM that increase our vulnerability to glaucoma.
青光眼的风险由前段的微观解剖结构和功能驱动。我们对两只人眼的流出道进行了计算密集型、高分辨率、全厚度带状扫描共聚焦显微镜 (RSCM) 检查。我们假设与现有的猪眼数据相比，这将揭示重要的物种差异，猪眼是一种不会自发发生青光眼的动物。
用凝集素-荧光染料缀合物和苯甲醇苯甲酸苄酯 (BABB) 对两只 80 岁老人的眼睛进行灌注后，通过 RSCM 对前段进行扫描，并在 3D 中进行重建，以进行全标本渲染。对小梁网 (TM)、角膜缘和角膜缘周围的流出道结构进行形态计量学分析，并与现有的猪眼数据进行比较。
RSCM 提供了高分辨率数据，可用于基于 IMARIS 的 3D 流出道结构表面重建。与具有丰富相互连接、狭窄和短收集管 (CC) 的猪眼不同，人眼的 CC 较少，其横截面积 (CSA) 大 1.5 倍，长度长 2.6 倍。施莱姆管 (SC) 水平的近端 CC 开口的 CSA 比进入巩膜血管丛 (SVP) 的远端开口大 1.3 倍。CC 的体积比接收 SVP 血管小 10.2 倍。长睫状神经的轴突——Axenfeld 环也被可视化。
在这项高分辨率、体积 RSCM 分析中，人眼的流出道血管比猪眼少得多。人眼的 CC 跨越几个时钟小时，比猪眼大。这些物种差异可能指向 TM 下游的增加我们患青光眼易感性的因素。
