:scowl: Why are you looking at your left hand? You need to get to a point where you just know where the notes are without looking, something I try to enforce from lesson one so the habit doesn't begin. Your arm/fingers/muscles to to know, not your eyes as you don't play with those!
Always a problem that develops without the reason to sight read, stands to reason if your eyes are reading the music, and your periferal vision is watching a conductor, then you cannot be looking at your hands.
When we learn we use line of sight on both hands, one to look at the fret, then a look at the string we pluck, or visa versa. The need to look at our hands diminishes as we progress, the reading of music ends any association with visuals of the instrument....our ears tell us what we are doing. With trained players this is all over and done with in months, because the need to read and play overrides any failings in technique.
I would even add that not being able to read and play would get the player throwing out/off the course/training because they are not cut out for it after a year.....come back when you are ready sort of deal.
I know many great players that look at their hands, they have a great ear and that suits them and their situation fine. I even worked with a guitarist that never looked at the neck, and I mean never. But put him on a stage with low lighting, moving lighting, or lights that would glare him and it becomes an issue. It's like, he does not have to look because that is his choice, but knowing if he wanted to look, but not see anything, that is not his choice...I think it is a control thing more than anything, but he cannot play well in those situation, and that excuse of seeing the neck is what he uses.........even though we all know he never looks at the neck.