I'm not sure if this is the proper type of physics to post this under, but here I go: If you're nearsighted, take your glasses off, with four fingers form a tiny square-like peeking hole, and bring the hole up to your eye. You'll notice the images in the distance become sharper as if you put your glasses back on. The reverse, by my account, isn't true. If you form the square and look through it with your glasses on, the distant objects are as clear as before. I'd think it should be fuzzy (the same way if someone who isn't nearsighted wears your glasses, he sees nothing but blobs), but that seems not to be the case. How does this happen?