Cellular-resolution OCT reveals layer-specific retinal mosaics and ganglion cell degeneration in mouse retina in vivo.

SIGNIFICANCE: Cellular-resolution retinal imaging in mouse models is hindered by optical aberrations and speckle noise, limiting the ability to visualize and track individual cells in vivo. Overcoming these challenges is critical for advancing preclinical studies of retinal disease and therapy. AIM: We developed a wavefront sensorless adaptive optics optical coherence tomography (WSAO-OCT) platform designed to achieve reliable cellular-level imaging of the mouse retina. APPROACH: The system integrates real-time aberration correction with multivolume averaging to simultaneously improve image quality and suppress speckle noise. Imaging results were validated using immunohistochemistry, and the platform was applied to monitor retinal ganglion cell (RGC) degeneration following optic nerve injury. RESULTS: WSAO-OCT improved image contrast by 61% and sharpness by 55%, whereas averaging 50 volumes markedly reduced speckle noise. The system enabled visualization of individual cells across all retinal layers and the retinal pigment epithelium. Immunohistochemistry confirmed that 95% of optically detected cells in the RGC layer corresponded to true RGCs. Following optic nerve injury, en face RGC counts enabled by the platform proved more sensitive than conventional layer thickness metrics of RGC loss, detecting significant RGC degeneration earlier (day 3 versus day 5) and with a greater magnitude (62% cell loss versus 8% thickness reduction) over one week. CONCLUSIONS: WSAO-OCT provides a noninvasive, quantitative, and cell-specific imaging tool for preclinical retinal research, offering translational potential for longitudinal monitoring and therapeutic evaluation.