Effects of BluTech Lenses on Melatonin, Sleep, Mood, and Neurobehavioral Performance

Objective. We examined the effects of modifying short-wavelength blue light exposure on evening melatonin levels, sleep, mood and cognition. Background. Intrinsically photosensitive retinal ganglion cells respond to short-wavelength light and contribute to circadian rhythm entrainment. Evening light exposure can cause melatonin dysregulation, which is associated with impaired mood and performance. Methods: A randomized controlled trial with crossover-design evaluated BluTech Lenses (blue light filter) versus clear lenses with anti-reflective coating only (control). Twenty-four students wore these lenses after 6:00pm for five days (Mon.-Fri.). Actigraphy watches non-invasively recorded sleep patterns each night. On the fifth evening, saliva samples were collected to quantify melatonin levels, and self-reported mood and neurobehavioral performance were assessed with the NIH Toolbox Emotion and Cognition batteries, respectively. Results: A significant increase in melatonin levels was measured with BluTech Lenses compared to control (9.6 vs. 4.9; p=0.036). Sleep onset latency was slightly reduced with Blutech Lenses, but not significantly different between glasses (p=0.20). Pattern comparison was significantly improved after wearing BluTech Lenses (p=0.04), while other aspects of cognition were not significantly affected (p\u3e0.05). A reduction in number of sleep awakenings was significantly associated with improved pattern comparison test scores (p=0.047). Changes in measures of mood were not significantly related to use of BluTech Lenses. Conclusions: BluTech Lenses appear to help regulate melatonin and can potentially be applied to at risk in order to lessen the deleterious effects of nighttime light exposure. Grants. Funding was provided by a grant from the US Department of Education: Science Peer & Research Collaboration