If you close your left eye, what do you see? If you close your right eye, what do you see? If you don’t see anything, you forgot to open your left eye again!
The two images you saw were probably pretty similar. Your brain knows that and is able to put the two images together and make one single image.
With two eyes, we have a wider field of vision and can see more than we could with just one eye.
In a 3-D world, having two eyes helps us figure out how far away something is. Our eyes need to focus, or point themselves in certain ways, differently in order to see things at different distances. To see something very far away, our eyes can pretty much point straight forward. To see things really close, our eyes will have to slightly turn toward each other. The different focuses helps our brain figure out what is far away and what is really close!