Inverting Spectacles Complete with two fully rotating inverting prisms in a shielded spectacle frame. The inverting prisms produce a lateral inversion of the rays – the world thus turns “upside down”. Besides being a lucid demonstration of the functioning of an inverting prism, experiments involving inverting spectacles encourage a better understanding of the visual process and the functioning of the brain. This also enables a better understanding of the visual perception of babies. Even the apparently simplest things in life (holding and picking up objects, drawing, orientating oneself in a room) become inconceivably difficult.