Why does this happen?!

Why does this happen?

so if ur tired and you try to focus steady on something it goes blurry. like i was trying to read something on my laptop and i stared at that one word and it went blurry after a couple of seconds of looking at it but when i blink its not blurry anymore.
i know of getting cross-eyed when the image gets distorted if you stare at it too long or something like that but is this also something that happens when u get cross-eyed?
i'd like to know if this happened to anyone else besides me also
cuz that was just strange.

1 week ago
i use glasses too, and contacts lol.
i just had my eyes checked very recently also, i got them dialated because the doctor was trying to figure out why my eyesight perscription was drastically changing but she said my eyes are very healthy and theres nothing wrong with them. i have a drastically changing perscription cuz it runs in my family i guess.

You may have a bit of esophoria (your eyes tend to turn in). Many people have this to some degree, but the eye muscles are able to accomodate for it. When you get tired, those muscles tire out, too, and they stop pulling the eyes out so that you focus.

Your optometrist probably did the measure at your last eye exam. Call his office and ask if you have a little esophoria or exophoria. If you do, that's the explanation...