Effects of Afternoon and Evening Light on Teenagers' Melatonin Levels, Alertness, Sleepiness and Sleep

"During the Dim light condition, the four-hour afternoon light exposure at the participants' eye level will be dim (\<5 lx melanopic EDI). In the 4.5-hour evening light exposure, this will constitute a light intensity of \~100 lx melanopic EDI at the participants' eye level."

"During the Moderate light condition, the four-hour afternoon light exposure at the participants' eye level will be dim (\~100 lx melanopic EDI). In the 4.5-hour evening light exposure, this will constitute a light intensity of \~100 lx melanopic EDI at the participants' eye level."

"During the Bright light condition, the four-hour afternoon light exposure at the participants' eye level will be dim (\>1000 lx melanopic EDI). In the 4.5-hour evening light exposure, this will constitute a light intensity of \~100 lx melanopic EDI at the participants' eye level."