Anyone experience this issue from using Nook Tablet?

I suppose it could be any tablet or e-reader. I’ve only had experience with the Nook Tablet.

I read a lot, sometimes just 20–30 minutes, sometimes hours. After I turn it off, and try looking elsewhere or reading elsewhere, I have trouble seeing, like my eyes are out of focus.

I’ve had this before when reading the computer or something close then try and focus on something farther away. Likewise with street signs too.

I know I need new glasses, its been 2 years, but even so.

Just thought I’d ask.