A smile lightens the heart and relaxes the body. It creates a postive outlook towards the project at hand. You certainly don't have to concentrate on keeping it there. It just helps relax you.
The same with the tangerine, it helps trigger the mind focus, you don't really keep your attention there only become aware of the top back part of your head if you find you have concentration difficulty.
The widening of your vision isn't attributed to the tangerine... it is part of the steps that you put in place yourself; a relaxed but focused state of mind. Just soften your gaze slightly, be relaxed and allow yourself to see groups of word rather than just one word at a time. Indeed, tsossczb, perhaps your field of vision is wide enough and you know when you are getting satisfactory results from photoreading.
Alex
