The Ballroom Dancer's vision affects head position, body position, balance, partnership, etc. When you want to correct these types of problems, the dancer's vision must change. What you see affects your partnership physically.
When we are driving on the highway and changing lanes, it seems that we always run over the reflector lane markers. You look at the marker to try to avoid it but you run over it any way. When driving, where you are looking is where you go. If you look at the reflector you will run over it. Look at a spot between the reflectors and you won't hit it. Your body adjusts unconsciously to what you see.
When I first started dancing, my instructor kept saying to me, "Keep your head up". It would stay up for a while then return to the down position. No matter how hard I tried it would eventually go down. I finally realized that I was wearing my glasses while I was dancing. With my head in the correct position, I would be looking through the bifocal portion of my glasses and my vision would be blurry. As I started dancing, I would unconsciously put my head down to look through the top part of my glasses in order to see clearly. I had two fixes, don't wear my glasses while dancing or consciously allow my vision to be blurred. Both fixes work.
I had been working on a Waltz dance routine for my first ballroom competition for about two months and I knew it inside and out. For some reason I had to practice the routine in another ballroom. I was completely confused in the different ballroom. Again I finally realized that I was associating the routine elements to the ballroom walls I was seeing. In the new ballroom I saw new walls and was confused. The solution was to ignore the walls and focus on the sequence and feeling of the routine. A dancer can unconsciously get attached to what they are seeing. This is usually a guy kind of problem.
The dancer's proper head position is fundamentally "nose and toes". The ladies nose points in the same direction as the ladies right toe. The man's nose points in the same direction as the man's left toe. This accommodates balance and direction of movement. The dancer's vision must change for this to be effectively accomplished.
The partnership offset position is often a problem. The partners drift across to eventually become nose to nose to each other. If the partners look at each other while they are dancing, they will eventually end up nose to nose. What each partner is seeing must change to correct this problem. If what they are seeing doesn't change, the partners will end up nose to nose.
It is very common for dancers to have the habit of looking down at the floor. This causes untold balance and partnership problems. This becomes a habit in their normal life and infiltrates their dancing. Ballroom dance floors are smooth and without obstructions. There is no reason to look down at the floor. The dancer has to change what he/she is seeing to maintain the correct head position. It is hard to change just on the dance floor. For the change to be effective the dancer needs to change his/her normal life. Instead of looking down at the floor, simply look further down the floor.
As illustrated in the above examples, what the Ballroom Dancer sees has a dramatic affect on his/her dancing. Most of the time dancers are not aware that what they are is causing a problem. Changing what the dancer sees has to be a conscious decision. It doesn't happen on its own. A change in vision needs to become part of the dancer's daily life. It is hard to change what the dancer sees only when they are on the dance floor. A dancer can change all kinds of things to improve their dancing, but if they don't change what they are seeing, the change won't be permanent.