Visualizing Micro-anatomical Structures of the Posterior Cornea with Micro-optical Coherence Tomography

Diagnosis of corneal disease and challenges in corneal transplantation require comprehensive understanding of corneal anatomy, particularly that of the posterior cornea. Micro-optical coherence tomography (μOCT) is a potentially suitable tool to meet this need, owing to its ultrahigh isotropic spatial resolution, high image acquisition rate and depth priority scanning mode. In this study, we explored the ability of μOCT to visualize micro-anatomical structures of the posterior cornea ex vivo and in vivo using small and large animals. μOCT clearly delineated cornea layers and revealed micro-anatomical structures, including not only polygonal endothelial cells, stellate keratocytes, collagen fibres and corneal nerve fibres but also new structures such as the dome-shaped basolateral side of endothelial cells and lattice structures at the interface between endothelium and Descemet's membrane. Based on these observations, a short post-harvest longitudinal study was conducted on rat cornea to test the feasibility of using μOCT to monitor the quality of endothelial cells. This study successfully reveals a series of morphological features and pathological changes in the posterior cornea at the cellular level in situ and in real time with μOCT. These findings enrich knowledge of corneal anatomy and suggest that μOCT may be a promising imaging tool in corneal transplantation.