The condition he wants me to avoid is called nearpoint stress, but sounds very similar to me (a layperson). It culminates in your eyes lenses becoming "stuck," unable to fully relax to focus properly on things at a distance. I guess the reason is that your cilliary muscles (that alter the shape of the lens) become overworked to the point of a spasm.
One symptom of that is looking up from your computer and objects being blurry for a few seconds, but then coming into focus.