I heard about eye strain from reading making my eyesight worse. I like to read books for fun a lot, but someone told me my eyesight will get worse from staring at books for an hour or two at a time (or more), and that I should look at something far away every now and then to refocus or relax my eyes.
Is there any truth to this? If so, how often should I look far away? Two minutes for every hour of reading? More? Less?