A method is provided for observing structure and function of individual cells in a living human eye, comprising: using an adaptive optics optical coherence tomography (AO-OCT) system to image a volume of a retinal patch including numerous cells of different types, as for example, ganglion cells; using 3D subcellular image registration to correct for eye motion, including digitally dissecting the imaged volume; and using organelle motility inside the cell to increase cell contrast and to measure cell temporal dynamics.