He Sees All

As a person who now has a "lazy eye" (due to an injury), I can tell you that the brain chooses one eye to see through, and ignores 99% of the sight coming from the other unless you close your main eye.

I mean, you could still make it SEEM like your paying attention in class...

If im not mistaken the condition (if not due to an injury) is called Strabismus and you are correct the brain, being the awesome thing it is, is smart enough to ignore the line of sight the "bad eye" capturates.

*and you are correct, the brain (that mistake changed the whole meaning of the sentence).