Retinal ganglion cells.

How do we perceive the beautiful and rich world around us? Light from the external environment is focused onto the retina, our visual sensory organ. Photons are captured by photoreceptors - light sensors within the retina - and converted into electrical signals. These electrical signals are transmitted to the brain through the optic nerve. If each optic nerve transmits a 'pixel' of the visual scene, then the total number of optic nerve fibers defines our biological 'resolution'. Humans possess approximately one million fibers, meaning the image sent from the retina to the brain (retinal image) has at most about one million pixels (Figure 1A). Compared to today's high-end smartphone cameras with 40-50 million pixels, the retinal image is surprisingly coarse and far removed from the sharpness we subjectively experience.