Blue-light optical coherence microscopsy

Corneal disease is the fifth leading cause of visual loss globally. The cornea, the optically transparent and outermost part of the eye, is vital for light transmission. Currently, specular microscopy (SM) and in vivo confocal microscopy (IVCM) technologies are used in clinical settings for cell evaluation, offering very high lateral resolution to observe individual cells and even cell nuclei in corneal tissue. However, SM and IVCM have some disadvantages, such as limited field of view, resulting in prolonged image acquisition and processing time, and lack of volumetric imaging capability. Optical coherence tomography (OCT), which is a non-invasive imaging modality, systems mostly use low numerical aperture (NA) objectives combined with broadband sources such as supercontinuum, femtosecond lasers, and a less expensive alternative, super-luminescent diode, to achieve high axial resolution, but the low NA objectives ultimately limit the lateral resolution to tens of microns. Optical coherence microscopy (OCM) is an imaging modality based on OCT and confocal microscopy that incorporates large NA objectives to achieve high lateral resolution. In this study, we present a blue-light OCM system with a center wavelength of 450 nm and a 6 nm bandwidth. We demonstrated high lateral resolution images of ex vivo rabbit corneal cellular structures such as epithelial cells, endothelial cells, keratocytes, and stromal collagen lamellae.