If you spend more than a couple hours a day on your phone, I have to warn you: it *will* damage your vision, and you won't notice right away.
The opaqueness of their nominal function to your mind is so perfect that we think of eyes like a glass lens with a default state, but your eyes don't resolve anything useful when inert. They are a system of muscles in counter tension pulling your eye's geometry into the required shape at all times. Sight is a thing of active maintenance, and their unconscious maintenance will fall apart without some conscious maintenance decisions. Here, most importantly, adequate sleep and limiting close focus.
I'm not explaining it very well, but I just wanted to emphasize how much I just didn't understand what a ... meaty pile of muscles the eyes really are, and how they can get worn out and screwed up just like any other muscle in your body, just literally by spending too much time looking at something.
