Short sighted are also known as nearsightedness or myopia. People with short sighted have problem to see far but have no problem to see near object. While long sighted is also called farsightedness or hyperopia. And people with long sighted have problem to see near objects but still good vision to see far. And these vision problems can be caused by heredity, and life style etc. And the best way to treat these problem is wearing prescription eyeglasses or contact lenses.
Well,I guess these r really very normal.It is known to all that people who r long sighted can't see things clearly near.On the contrary,people who r shortsighted can't see things clearly in a distance and that is why most elder people will get longsighted cuz longsightedness just grow as u age.However,young people r more likely to suffer from shortsightedness cuz of some bad habits.