Hey PaulD, are you the same guy from F1-live site?

Anyway, about photoreading making your eyes sore, I had the same problem initially. I think what you are doing is that you are trying to force your eyes at the same time to focus on the pages and beyond the pages. There is a confclict there and it makes your eyes sore (eye muscles). Forget focusing on the actual pages. Try for example to hold the book on your lap. First look at your feet and keep your focus there. Then move the book in front of your field of view and see if you try to focus on the pages or beyond them. Once you get the knack of focusing beyond the book your eyes can take endless hours of photofocus without any strain. In the end I can see the words clearly (even though of course I don't read them) and the blip page. It's kind of weird, you don't have that effect in other things in life in my opinion.