Why does vision become blurry/out of focus when you zone out and stare at one point?

Question

Why does vision become blurry/out of focus when you zone out and stare at one point?

In: Biology

Answer 1

Your eyeballs have small muscles inside them that bend the lenses of your eyes (corneas). That’s how focusing works.

When you relax your eyes, you’re relaxing those muscles. Whatever tension they were maintaining to keep your vision focused on the thing goes away, so your focus goes away.