The eye was not made to be constantly focused on close objects.
If your work requires that you stare at a computer screen all day long or if you watch a lot of television, stop from time to time to do a few eye exercises.
For example, roll your eyes in large circles in both directions;
look over to each side as far as possible and then go from up to down; or scan an imaginary text on the wall from left to right; or look out the window as far as you can following the horizon then return to a point right in front of you and begin again.
In this way, you will avoid long term eye problems, you will enlarge your inner space, and relax both your eyes and your mind.