![The Evolution of the Human Eye](https://hight3ch.com/wp-content/uploads/2015/01/the-evolution-of-the-human-eye.jpg)
The human eye is an amazing mechanism, able to detect anywhere from a few photons to a few quadrillion, or switch focus from the screen in front of you to the distant horizon in a third of a second. How did these complex structures evolve? Joshua Harvey details the 500 million year story of the human eye.