From: Circadian and Wake-Dependent Effects on the Pupil Light Reflex in Response to Narrow-Bandwidth Light Pulses Invest. Ophthalmol. Vis. Sci.. 2012;53(8):4546-4555. doi:10.1167/iovs.12-9494 Figure Legend: (A) Salivary melatonin concentrations averaged per circadian phase (15° = 1 hour) and double plotted (mean ± SEM, n = 10). Dashed line: averaged DLMO threshold for melatonin concentration (2.2 pg/mL). (B) Averaged subjective sleepiness ratings collapsed into 2-hour bins with respect to elapsed time since wakefulness (mean ± SEM). Grey area: the 12-hour nighttime session. Date of download: 10/24/2017 The Association for Research in Vision and Ophthalmology Copyright © 2017. All rights reserved.