The world we "see" is a figment of our imagination. Our minds do not generate images in the same way that a video camera does. Instead, the brain builds a model of the world using data from modules that measure light and shade, edges, curvature, and so on. This allows the brain to easily paint out the blind spot, which is the area of your retina where the optic nerve connects and has no sensors. It also compensates for our eyes' rapid, jerky movements, known as saccades, creating the illusion of steady vision.