Everything we see is really just light focused onto the back side of your eye. Essentially your retina is like a tiny little movie screen for all of our images to play out on. It is covered with over 100 million photoreceptors to help give your own personal movies color and shape. This is also a good place to mention that the images are all upside down. Or maybe we are the ones upside down? Either way, these images get flipped and sent to our brain via the optic nerve. Every time I read about light, the eye, optical illusions, and how we see things I am amazed. There is an article on NPR about light and how we see and that seeing is not merely the reception of signals but that it is really more like dancing (go read it...and have your mind blown...or at least something to chew on for a while http://www.npr.org/blogs/13.7/2014/01/12/261230681/seeing-the-world-is-like-dancing-with-it ) Or if you are a Vsauce fan, watch the one on color and spend the rest of your day w...