Your retina has two types of photoreceptor cells, rods and cones. Rods detect light intensity rather than colour, they are what enable you to see in the dark. This is why as light levels drop it gets harder to see colour. Photons of light are detected by chemicals within the outer segment of the rod, I’ve shown these segments like large antennae here. The inside of the cell is a stack of light-sensitive discs which convert the electromagnetic energy of the photon into chemical energy and then electrical impulses. These signal to the rest of the retina and then the brain that light has been detected. At some point, I’ll provide a more detailed explanation of how the visual system works, for now, I hope you enjoy the cartoon especially if you’re reading it in dark mode.
