Stromal nerve imaging and tracking using micro-optical coherence tomography

Purpose: To image, track and map the nerve fiber distribution in excised rabbit corneas over the entire stromal thickness using micro-optical coherence tomography (μOCT) to develop a screening tool for early peripheral neuropathy. Methods: Excised rabbit corneas were consecutively imaged by a custom-designed μOCT prototype and a commercial laser scanning fluorescence confocal microscope. The μOCT images with a field of view of approximately 1 × 1 mm were recorded with axial and transverse resolutions of approximately 1 μm and approximately 4 μm, respec-tively. In the volumetric μOCT image data, network maps of hyper-reflective, branched structures traversing different stromal compartments were segmented using semiautomatic image processing algorithms. Furthermore, the same corneas received βIII-tubulin antibody immunostaining before digital confocal microscopy, and a compari-son between μOCT image data and immunohistochemistry analysis was performed to validate the nerval origin of the tracked network structures. Results: Semiautomatic tracing of the nerves with a high range of different thicknesses was possible through the whole corneal volumes, creating a skeleton of the traced nerves. There was a good conformity between the hyper-reflective structures in the μOCT data and the stained nerval structures in the immunohistochemistry data. Conclusions: This article demonstrates nerval imaging and tracking as well as a spatial correlation between μOCT and a fluorescence corneal nerve standard for larger nerves throughout the full thickness of the cornea ex vivo. Translational Relevance: Owing to its advantageous properties, μOCT may become useful as a noncontact method for assessing nerval structures in humans to screen for early peripheral neuropathy.