system
Given the following post, respond as if you're commenting on Reddit:
human
Why does vision improve when one is squinting?
gpt
This is actually more of an optics question than a biology question. When light passes through a small hole, it becomes focused because the hole is limiting the paths that the light can take. The smaller the hole, the more focused it becomes, but the dimmer it becomes (because it's letting less light through).

When you squint, the light becomes focused by traveling through the small gap in your eyelids, and the effects of your eyes' lenses decrease.

For more information, you can look up pinhole cameras, or camera obscura. It's pretty interesting stuff.