Does 20/20 Vision And Amblyopia Cause Extreme Dizziness?

My14 yr old daughter (that has Autism/Asperger s) cant walk up stairs without getting dizzy. She also panics when we walk around the second level of the mall or library. Something about being able to look down makes her dizzy. This is something she did mildly as a small child, but now it is getting more extreme. Could this be vertigo? Her eye doctors say she has 20/20 vision and has Amblyopia.