This episode takes viewers on a fascinating tour of our visual world, from the moment light enters our eyes, to the way this information is transformed into electrical impulses and decoded by our brain – the domain of "visual perception". Seeing takes an immense amount of brainpower, more than 65% of the brain's neural pathways. This massive machinery has been intensely studied, and yet scientists continue to be surprised by what we see with our eyes and actually perceive with our brains. Viewers will literally see with "new eyes" as The Nature of Things explores the complexity and quirks of sight. World-class scientists will share the stories of new discoveries and what they have learned by studying patients suffering from a variety of visual disorders. Those personal stories will anchor the film as we reveal, in startling ways, how our eyes and brain trick us into seeing the world.