Shortsighted means not taking into account the long-term effects of your actions.
In British English, shortsighted can also mean nearsighted, meaning that your vision is blurry at a distance.
Only being able to see well at short distances.
careless, blind, ill-considered, unwary, stupid
Seeing distinctly at short distances only; shortsighted.
Seeing distinctly at short distances only; shortsighted.
Stinting on funding for education strikes many people as shortsighted.
short, shortsighted, unforesightful, myopicimprovident (vs. provident)
shorty shortish shortest shortness
Nearsighted is a word. It is the opposite of foresighted.
The ignorant fool was too shortsighted to see that the medical practices were not witchcraft, but science.
Nothing serious would happen if you chose not to care about your myopia. However, it could cause you to become more nearsighted or shortsighted due to not correcting it.
Yes, we can see things much closer (depending on level of short-sightedness). I have found it to be to my advantage when painting details on small models, I can bring the model right up close to my eye and see it clearly when I flick up my glasses, and see it comfortably. If I am wearing glasses (or contact lenses), I cannot focus on the object so close, and it becomes uncomfortable. There is a scientific explanation for this that I once read, to do with the shape of the myopic eye.
People wear glasses because they are either longsighted or shortsighted. People who wear glasses may have circles under the eyes because it is the imprint of the glasses.