You like your eyes, right?Â We certainly like ours.Â Most of the time they work awfully well — despite a massive design flaw that any first-year engineering student would have caught.
It’s called the punctum caecum, an area at the back of the eye that the optic nerve passes through, obscuring the light-sensitive photoreceptor cells that make vision possible.
That blind spot also makes an awesome optical illusion possible. Richard Wiseman, who runs the Quirkology video channel on Youtube, has concocted a particularly striking demonstration of the human blind spot — by making his own head disappear! Weirder yet, he’s able to pass a black bar up and down within the blindspot and it still seems visible, because the human brain is capable of reconstructing such simple objects and filling in the gaps.
See — or don’t see — for yourself: