my niece's eye began to turn in towards her nose all of a sudden. what could be doing this?

Answer 1

That happpened to my grandson. The muscle in the eye is weak .. He had to have surgery to have it repaired, cause if they wait till he was older the muscle would have been stronger thus harder to move by surgery. He was about 3 or 4 years old when this happened.

Answer 2

Could be lazy eye. That can be fixed with an eye patch over her good eye. It is most common during childhood.