DD is almost 7 years old and has shown an interest in reading. She shares a bunk bed with DS who is 4 years old (DD on the top bunk). They go to bed at the same time as DS struggles fall asleep without her in the room. I feel DD should be staying up a bit later but thought maybe I could get her one of those lamps that clip onto the side of the bed so she can stay up and read a little? Would this be bad for her eyes? I don't really want to keep her up downstairs as she finds it difficult to switch off and will bounce around getting emotional because she's tired and struggling to wind down.