I am sure this does not mean you are going blind. How many people as a rule would spend any amount of time doing what you asked people to do? Most probably none. I could ask you to hop on one leg whilst holding your breath and tell you that after a while you will feel dizzy. Does this mean there is something wrong with you? Or is it just the fact that you did what I asked and it brought on the dizzy symptoms. In other words if you keep on looking for things you will always find them.