My experience has been that the further the book is from my eyes, the smaller the blip page until it vanishes completely. That being said, there are many times when I am PhotoReading that I don't even see the blip page, but still have the relaxed gaze that allows me to see both pages without fixating on individual words.
Keep the eyes relaxed, blink freely - whenever you feel the need. One of the basic keys to the whole system, and to accelerative learning in general, is to relax. Ideally, I think, there should be zero eyestrain in the process of PhotoReading and any strain that occurs in the early stages is due not to the PhotoFocus state itself, but is due to trying to hard to get the state. Once more, relax the gaze. If you see the blip page, great. If not - no big deal. If the words are blurred, that's okay. If they are clear, fine. The idea is not to deliberately defocus the eyes, nor to cross them. Instead, just gaze and take in both pages at the same time. The PhotoReading book gives several alternative techniques for using the eyes while PhotoReading. Play with them all.