I brought this question to our PhotoReading instructor, Cheryl Hiltibran, and here is her response:

"I recommend as an instructor, if you recognize your mind is wandering you may not be flipping the pages fast enough to stay more connected with the content of the book or text.

But also, notice what your daydreams are and refer to the text to determine if the daydreams are connected to the subject you are reading. You have to go back to the text, activation, etc, to validate your daydreams, before you dismiss their potential value.

Ask yourself, could the daydreams be your plan for implementing the material later? If that is true, you are demonstrating "High Order Thinkng" which is great!

Being aware of whether you feel anxious or bored while flipping, is the guideline of knowing whether you are in an optimal state for absorbing the material or not.

Being aware of the corners of the pages isn't as important as being aware that you are actually using your full peripheral vision/awareness, which is 99% of your vision."