I think you'll find that the "screen brain" effect dissipates after about 20 minutes of discomfort. I've noticed this effect with novels and text books.
Note that I don't think it's a great idea to just "read through" an 800 page text book even if you can - you've got to do exercises and check your own knowledge or else you will be spinning your wheels.
> I think you'll find that the "screen brain" effect dissipates after about 20 minutes of discomfort
You mean one should persevere for more than 20 minutes and then can easily focus on the book? If so, that's great news! Note that I suffer from the "screen brain", but it's always good to know how brain works.
Note that I don't think it's a great idea to just "read through" an 800 page text book even if you can - you've got to do exercises and check your own knowledge or else you will be spinning your wheels.