Tight Vision - What's that?

I was talking to one of the doctors at my daughter’s vision therapy the other day. I was commenting on how before we started the therapy she would never guess and now she does (some). The doctor was saying that she has what they call tight vision. She asked if her personality was loosening up as we loosened her vision. It was a light bulb moment. She has mellowed a lot. I thought it was just a confidence thing, but now I can see that it's more than that. The brain is such an amazing thing.