Graphic design

Hello. I have a really poor black and white image that I would like to use for an NHS patient information leaflet. I would like it to be in colour and I would like the person's head to be a real head if possible. It may be printed out by some patients and I would appreciate suggestions for a better way to distinguish the different visual fields and the overlapping area (you will see what I mean when you see the image). I have uploaded the image in word and also Pdf as I am not sure what is best for graphic designers. Many thanks