What Causes Seeing Of Different Colors In Vision Of A 5 Year Old?

Hi there. My 5 year old daughter occasionally complains that her eyes are bothering her. She says that things are different colours than they should be, such as a cushion she knows to be cream looks purple to her. At first I put it down to her imagination but over the last year she has mentioned it at least 5 times to me, so now I am wondering if I should bring her to have her checked out. Could this be a symptom of a disease that I am unaware of?