Visible-light optical coherence microscopy

Corneal diseases are the fifth leading cause of visual loss globally. Current clinical imaging instruments such as in vivo confocal microscopy (IVCM) offer high lateral resolution to observe cellular structures but lack large field of view and volumetric imaging capability and require high operator skill to focus and align. To overcome these limitations, we have developed blue (450 nm) and green (510 nm) light optical coherence microscopy (OCM) to image cellular structures. Imaging was demonstrated in ex vivo samples including human donor eyes. The OCM systems were based on a spectral-domain optical coherence tomography engine and achieved 750 µm × 750 µm field of view, 1.2 mm imaging depth, and 1.6 µm lateral resolution. Epithelial cells, endothelial cells, and keratocytes of ex vivo rabbit cornea were visualized. Additionally, collagen fibers were observed in stromal lamellae with striated patterns. En face and cross-sectional images of trabecular meshwork and Schlemm’s canal in a donor human eye wedge were observed at various trans-meshwork pressures controlled by cannulation of the canal. Microbes such as filamentous fungi and bacteria were observed.