Larry A Donoso Laboratory for Eye Research, Division of Ophthalmology and Visual Sciences, School of Clinical Sciences, Division of Histopathology, University of Nottingham, United Kingdom.
Ophthalmology. 2013 Sep;120(9):1778-85. doi: 10.1016/j.ophtha.2013.01.018. Epub 2013 May 25.
To define and characterize a novel pre-Descemet's layer in the human cornea.
Clinical and experimental study.
We included 31 human donor sclerocorneal discs, including 6 controls (mean age, 77.7 years).
Air was injected into the stroma of donor whole globes (n = 4) and sclerocorneal discs (n = 21) as in the clinical deep anterior lamellar keratoplasty procedure with the big bubble (BB) technique. The following experiments were performed: (1) creation of BB followed by peeling of the Descemet's membrane (DM); (2) peeling off of the DM followed by creation of the BB, and (3) creation of the BB and continued inflation until the bubble popped to measure the popping pressure. Tissue obtained from these experiments was subjected to histologic examination.
Demonstration of a novel pre-Descemet's layer (Dua's layer) in the human cornea.
Three types of BB were obtained. Type-1, is a well-circumscribed, central dome-shaped elevation up to 8.5 mm in diameter (n = 14). Type-2, is a thin-walled, large BB of maximum 10.5 mm diameter, which always started at the periphery, enlarging centrally to form a large BB (n = 5), and a mixed type (n = 3). With type-1 BB, unlike type-2 BB, it was possible to peel off DM completely without deflating the BB, indicating the presence of an additional layer of tissue. A type-1 BB could be created after first peeling off the DM (n = 5), confirming that DM was not essential to create a type-1 BB. The popping pressure was 1.45 bar and 0.6 bar for type-1 BB and type-2 BB, respectively. Histology confirmed that the cleavage occurred beyond the last row of keratocytes. This layer was acellular, measured 10.15 ± 3.6 microns composed of 5 to 8 lamellae of predominantly type-1 collagen bundles arranged in transverse, longitudinal, and oblique directions.
There exists a novel, well-defined, acellular, strong layer in the pre-Descemet's cornea. This separates along the last row of keratocytes in most cases performed with the BB technique. Its recognition will have considerable impact on posterior corneal surgery and the understanding of corneal biomechanics and posterior corneal pathology such as acute hydrops, Descematocele and pre-Descemet's dystrophies.
FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.
定义并描述人类角膜前 Descemet 层内的一种新的结构。
临床和实验研究。
我们纳入了 31 例人类供体巩膜角膜环，包括 6 例对照（平均年龄，77.7 岁）。
空气被注入供体全眼球（n=4）和巩膜角膜环（n=21）的基质中，方法类似于临床深板层角膜移植术中的大泡（BB）技术。进行了以下实验：（1）BB 形成后剥离 Descemet 膜（DM）；（2）DM 剥离后形成 BB；（3）形成 BB 并持续充气直至气泡爆裂以测量爆裂压力。从这些实验中获得的组织进行组织学检查。
在人类角膜中证明存在一种新的前 Descemet 层（Dua 层）。
获得了 3 种 BB。1 型 BB 为界限清楚的中央穹顶状隆起，最大直径达 8.5mm（n=14）。2 型 BB 为薄壁、最大直径达 10.5mm 的大 BB，其始终从周边开始，向中央扩大形成大 BB（n=5），以及混合型（n=3）。对于 1 型 BB，与 2 型 BB 不同，它可以在不使 BB 放气的情况下完全剥离 DM，表明存在额外的组织层。在首先剥离 DM 后（n=5）可以形成 1 型 BB，这证实了 DM 对于形成 1 型 BB 并非必需。1 型 BB 和 2 型 BB 的爆裂压力分别为 1.45bar 和 0.6bar。组织学证实，裂层发生在最后一排角膜细胞之后。该层无细胞，厚度为 10.15±3.6μm，由 5 至 8 层主要为 1 型胶原束组成，排列方向为横向、纵向和斜向。
在前 Descemet 角膜中存在一种新的、明确的、无细胞的、坚固的层。在大多数情况下，使用 BB 技术进行操作时，它从前部角膜细胞的最后一排分离。其识别将对后部角膜手术以及对角膜生物力学和后部角膜病理学（如急性水肿、Descemet 囊和前 Descemet 营养不良）的理解产生重大影响。
作者在本文讨论的任何材料中均没有任何专有或商业利益。
