I am reopening this post topic because I can add my own personal experience to this topic.
Absolutely, yes you can have permanent eye damange cause by excessive use. It happened to me. I lost my job of over 20 years because of it. I can barely watch T.V. or go on computer. I did all the "usual stuff they tell you to do, ergonomically and it still didn't help." My employer didn't allow the employees to rest their eyes, except for the regular schedule breaks. I've been to numerous specialist. Opthamologists, Neurologists. I've had cat scan's, Mri's, you name it. All these "specialists" claimed my eyes would go back to normal after I rested them for a while. I was off an on at work for a good couple of years and was eventually had to leave as I couldn't take the severe headaches. I used to love reading books and now I can barely read a headline in a newspaper.
The bottom line is that the experts themselves haven't bothered to investigated this problem in a great studies at all. They are only a few studies out there. I believe Japan was one of them.
If there are other people out there with a similar situation I would love to hear from you.
I wish to God I knew what would happen, but I made the mistake of listening to the "experts". I had left that job 2 years ago and the problem still hasn't gone away and I can't find any Doctor that will at least acknowledge that it can be permanent.
If you find your eyes, going like this, run don't walk, out of the profession of sitting in front of a computer all day before you end up like me...
because there is no turning the clock back.
A cautionary tale, but a true one...