In EEG protocol description, (resting state)

"Participants are instructed to open or close their eyes at various points."

Q1. What is the point of closing or opening the participant's eye?
      - We want to know when the participant's eyes are opened or closed.
      - What are the various points?

Q2. If you give instructions to participant in the resting state to open or close their eyes, can we get that point (instructed timing)? 

Thanks