0311 Partial blue light blocking glasses advanced sleep phase but did not alter salivary melatonin secretion in Japanese schoolchildren

Abstract Introduction A late bedtime is one of the most common characteristics sleep habits in modern society. This also case for schoolchildren, with negative consequences their academic performance. Light exposure at night, particularly blue wavelength light, was thought to delay bedtime, and melatonin suppression via light considered be mechanisms responsible delayed phase. Methods In current study, we evaluated effects partial blocking glasses (JINS Screen Lens Heavy [40%cut]) on salivary levels, circadian phase daytime behavior (via actigraphs questionnaires), without Standard Clean Lens) 39 male school children (ages between 10-12). The study design a cross over design, respective worn 3 hours before habitual two weeks, one-week washout period (with own regular glasses) sessions. Saliva collections questionnaires were performed during first second weeks each session, saliva collected -3, -2, -1, 0 bedtime. Actigraph data throughout evaluation periods. Results We found that while had no effect they did significantly advance compared non-filter session (bedtime: 22.03±0.08h vs. 22.1±0.1h, onset: 22.26±0.08h 22.36±0.10h, p= 0.04). filter noticeable week, where significant advances (-0.12h, p=0.03), onset (-0.14h, wake up time (-0.13h, p=0.02), leaving-bed p=0.02) from 1st week observed, whereas changes seen control (without filter). Along advancement irritability acting out towards siblings friends reduced session. Conclusion Our results suggest advanced improved but not mediated by secretion. Further research into involved warranted. Support (if any) supported Jins Holdings Inc (SPO236998).