You seem to be confusing anti depressants with either speed or tranquilizers.
Humans percieve much of their world through the sense of vision.
People are born with a propensity towards perfect vision, nearsightedness, farsightedness, etc. Sometimes they just develop, and the kid needs glasses as soon as they can test for them. Brains are very similar to corneas. They shape perception into meaning. But they're also more complex.