Why Do We Have To Blink ?
It serves several functions. For one it keeps are eyes from becoming too dry, and it also helps "clean" our eyes of any microscopic dust/etc that managed to make it past our protective eyelashes.
To clean/keep our eyes wet.
We do this to keep our eyes moist and to keep out foreign particles
So our eyes don't turn watery then burn
To keep our eyes from drying out. It moisturizes with every blink.
Our eyes get dry and we blink to make them wet. When we blink a tear will cover our eye to make it moist.