Leaving the Light On

Barb likes to try to read in bed at night.  She doesn’t have to read much before she falls asleep.  Every night is the same; she falls asleep with the light on and her book open in the bed with her.  She often loses her page because her book mark falls out.  She eventually wakes up or I wake her up and puts her book away and turns off the light.  One night she didn’t wake up until early in the morning and she wondered why it was so light in the room even though it was still early.  Then she realized that I hadn’t woken her up and she had left the light on all night.