Hi ellascientist, that’s a great question! My PhD was on how and why we move our eyes, so hopefully I know the answer to this one. At the back of your eye, you have lots of cells called ‘photoreceptors’, which detect light that comes through the lens, and converts it into an electrical signal that is then passed on as information for the brain. All of these signals have to come out of your eye, so there’s an area at the back of your eye where the optic nerve starts, and all the information is sent along there. Because there aren’t any photoreceptors where the optic nerve starts, you can’t see anything in that particular part of your vision – hence, the blind spot!