From simple biological view, it's not.
Focusing your view on a distant point is made by lens in your eye changing it's shape.
Unless you spend 5 years of nonstop focusing on distant shapes, nothing will happen.
Of course if after focusing you look at things close to you, to make your lens go to other shape.
You should look about the same amount of time at distant and close points through your life, and if you don't have any eye worsening genes and you eat well, your eyes should be good
[with age lenses tend to congeal (people say it's because you dont eat butter ) and you may see worse, at this point of view
"letting your eyes focus on a distinct point could cause retinal damage if done too much" but only if you do it really much]
Do you understand, or should I post here how lenses in eyes shape to let you focus on distant and close shapes?