There are certain parts of your eye that you actually can’t see with. but your braind uses the other information it recieves to make up for it. One of the tests I had to do at my for my eye doctor was this thing where they have you look into one of those machines that are like binoculars and you click a button when you see a dot appear. they can then tell which parts of your vision tyou are blind in. It has to do with your peripheral vision and stuff. Its pretty neat actualy.