Figure 2

Entrainment phase angle distribution for a population of 200 simulated individuals with a normally distributed intrinsic circadian period with means (± SD) of 24.15 (± 0.2) h33. Illuminances refer to corneal light exposure (i.e., at the eye) for daytime (wake-19:00) illuminance (L1) set to the values indicated on the x-axis. Evening light exposure L2 was simulated at 30 lx from 19:00 until sleep onset. The central marker indicates the median, and the bottom and top edges indicate the 25th and 75th percentiles, respectively. The whiskers extend to the most extreme data points (population minima and maxima).