Our visual system is mesmerising. It is our predominant means of corresponding with the outside world, allowing us to navigate safely through traffic, spotting the mosquito bugging us at night, or reading blogs like this on our phone, tablet or computer. To make things visible, the very first process going on inside our bodies is the transformation of light into neuronal signals on the retinas of our eyes. To do this, our retina is equipped with so-called rods and cones, photoreceptors that turn light photons into electrical signals. Rods are good at sensing light-dark differences while cones come in three different types, each responding best to different wavelengths or colours. Fun side note: Some women have superhuman vision because they carry two recessive genes on each X chromosome resulting in the expression of a fourth type of cone, thus enabling them to perceive additional colours! Overall, each of us has about 90 million rods (mostly in the periphery of our eyes) and 5 million cones (mostly in the fovea, or the centre, of our eyes). Simplifying this, our eyes have an initial resolution of 95 million “pixels”, which is far better than the full HD resolution of 1920×1080 (~2 million) pixels on our TVs.