In the morning and during the day and anytime you want to be alert, you want to flip on as many overhead lights as possible. This is because these cells in the eye that trigger activation and alertness of the rest of the brain and nervous system reside in the lower portion of the eye; they view the upper visual field. Now, the inverse of all this is also important—as you approach the evening or night time and you want to go to sleep, that is the time to start avoiding bright lights of any color, not just blue light, and, if possible, to place whatever lights are present in your environment lower in your visual field.