47-year-old Daniel Kish has been completely blind ever since he was just a baby, but that hasn’t stopped him from living an incredibly active life which includes riding a bicycle or hiking alone in the mountains. To do this, he has perfected a form of echolocation, the same mechanism bats use to see in the dark.
Daniel has been blind for as long as he can remember. He was born with an aggressive form of cancer called retinoblastoma, which attacks the retina, and at only 13 months, doctors had to remove both his eyes, in order to save his life. He now has prosthetic eyes. He has never seen a tree, a car, or another human being, but he is perfectly able to navigate and even describe his surroundings in close detail, using echolocation, a technique he has been practicing from a very early age. Basically Daniel uses sound to see. Every environment and surface has its own acoustic signature and he produces brief, sharp clicks with his tongue to identify them. The sound waves he creates travel at a speed of over 1,000 feet per second, bounce off every object that surrounds him, and returns to his ears at the same rate, though vastly decreased in volume, telling him exactly what everything is, and where it’s located.
