Sweetie, since you want to know more about our eyes. Please have a look at http://en.wikipedia.org/wiki/Eye. There are many zones in our eyes. Different part has different functions. I hope this helped and you can know more from this. Good luck!
the role of human eye is to help us see things and keep balance. But some blind people can keep balance too because they can keep balance by using other senses that we have. Dude, if you want to know something more professional, I suggest you to talk with your eye doctors. Good luck!