There's a lot of finely-tuned engineering that happens in a human body, especially in the eye. Our irises readily expand or contract depending on ambient light, and our lenses can easily focus on an object in, to pardon the pun, a blink of an eye.
It's no wonder that Instructables member T3h_Muffinator was so inspired by this marvel of optical engineering that he built a pair of bionic goggles that simulates the iris's reaction to light and distance. Not only that, these steampunk-ish robo-glasses are made entirely out of discarded materials.
He even left step-by-step instructions, just in case you want to build your very own pair.