Studies
Blue Light Blocking Glasses Studies
Burkhart & Phelps (2009) – “Amber lenses to block blue light and improve sleep: A randomized trial”
Journal: Chronobiology International
Population: 20 healthy adults (no mental health conditions specified).
Method: Participants wore amber blue-blocking glasses 3 hours before bed vs. clear lenses for 2 weeks.
Findings: Improved subjective sleep quality (Pittsburgh Sleep Quality Index scores) in the blue-blocking group. No objective sleep measures (e.g., actigraphy), but suggests a mild benefit for healthy sleepers.
DOI: 10.3109/07420520903523719
Bigalke et al. (2021) – “Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial”
Journal: Sleep Health
Population: 21 healthy adults (no chronic conditions or mental health issues).
Method: Blue-blocking glasses vs. placebo worn 2 hours before bed for 7 nights.
Findings: No significant change in objective sleep (actigraphy—total sleep time, efficiency) but a small improvement in subjective sleep quality (e.g., feeling more rested). Suggests limited but perceptible benefits.
DOI: 10.1016/j.sleh.2021.04.005
Nagare et al. (2019) – “Effect of exposure duration and light spectra on nighttime melatonin suppression and subjective sleepiness in healthy participants”
Journal: Sleep
Population: 16 healthy young adults (screened for normal sleep and health).
Method: Tested blue-blocking glasses under varying light exposures (2-3 hours before bed) vs. control.
Findings: Reduced melatonin suppression (a sleep-regulating hormone) compared to no glasses, suggesting better sleep readiness. Subjective sleepiness increased slightly, hinting at a circadian benefit.
DOI: Not directly available, but cited in Sleep Research Society archives (Vol. 42, Supp. 1).
van der Lely et al. (2015) – “Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers”
Journal: Journal of Adolescent Health
Population: 13 healthy male teenagers (no mental health issues).
Method: Blue-blocking glasses vs. clear lenses worn during 2-hour LED screen exposure before bed.
Findings: Increased subjective sleepiness and preserved melatonin levels compared to controls, indicating a protective effect on sleep onset in healthy teens.
DOI: 10.1016/j.jadohealth.2014.08.002
Journal: Chronobiology International
Population: 20 healthy adults (no mental health conditions specified).
Method: Participants wore amber blue-blocking glasses 3 hours before bed vs. clear lenses for 2 weeks.
Findings: Improved subjective sleep quality (Pittsburgh Sleep Quality Index scores) in the blue-blocking group. No objective sleep measures (e.g., actigraphy), but suggests a mild benefit for healthy sleepers.
DOI: 10.3109/07420520903523719
Journal: Medical Hypotheses
Population: Individuals with bipolar disorder.
Method: Participants wore blue light-blocking amber lenses in the evening as part of dark therapy.
Findings: Suggested that blocking blue light in the evening stabilized mood and improved sleep patterns in individuals with bipolar disorder.
DOI: 10.1016/j.mehy.2007.04.042
Journal: Proceedings of the National Academy of Sciences
Population: 12 healthy young adults.
Method: Participants read on either a light-emitting eReader or a printed book before bed for 5 consecutive nights.
Findings: Those using the eReader had suppressed evening melatonin levels, delayed sleep onset, and reduced next-morning alertness compared to the printed book group.
DOI: 10.1073/pnas.1418490112
Journal: Sleep
Population: 16 healthy adults.
Method: Participants were exposed to different wavelengths of light at night to assess effects on alertness and sleep.
Findings: Blue light had the strongest impact on delaying melatonin secretion and increasing alertness before bed.
DOI: 10.5665/sleep.3406
Journal: Chronobiology International
Population: Meta-analysis including multiple studies on sleep and blue light-blocking interventions.
Method: Reviewed published research on blue-light shielding and its impact on sleep.
Findings: Found some evidence of improved sleep outcomes, but results were inconsistent, and more rigorous trials are needed.
DOI: 10.1080/07420528.2017.1324878
Vagus Nerve Stimulators Studies(Coming Soon)
Beste et al. (2016) – “Effects of trans-cutaneous vagus nerve stimulation (tVNS) on cognitive control in healthy participants”
Journal: Scientific Reports
Population: 40 healthy adults (no mental health or neurological conditions).
Method: Non-invasive tVNS applied to the ear for 30 minutes vs. sham.
Findings: Improved cognitive control (reaction time, error rates) and a slight increase in subjective relaxation, suggesting a calming effect that could aid sleep prep. No direct sleep measures, but hints at health benefits.
DOI: 10.1038/srep25767
Warren et al. (2018) – “Transcutaneous vagus nerve stimulation (tVNS) enhances response selection during action cascading processes in healthy adults”
Journal: Frontiers in Neuroscience
Population: 24 healthy adults (screened for normal health).
Method: tVNS vs. sham for 20 minutes.
Findings: Enhanced focus and reduced stress markers (via heart rate variability), which could indirectly support better sleep and relaxation in healthy people. No sleep-specific data.
DOI: 10.3389/fnins.2018.00535
Burger et al. (2019) – “Transcutaneous vagus nerve stimulation and heart rate variability in healthy volunteers: A pilot study”
Journal: Brain Stimulation
Population: 17 healthy volunteers (no chronic conditions).
Method: tVNS applied for 15 minutes vs. sham.
Findings: Increased heart rate variability (HRV), a marker of parasympathetic activity linked to relaxation and better sleep regulation. Suggests a health benefit for stress reduction.
DOI: 10.1016/j.brs.2019.03.008
Clancy et al. (2014) – “Non-invasive vagus nerve stimulation in healthy humans reduces sympathetic nerve activity”
Journal: Brain Stimulation
Population: 48 healthy adults (no mental health or medical issues).
Method: Non-invasive tVNS vs. sham for 15 minutes.
Findings: Reduced sympathetic activity (fight-or-flight response) and increased parasympathetic tone, promoting relaxation. Could enhance sleep quality indirectly, though not directly measured.
DOI: 10.1016/j.brs.2014.03.010
Blue Light BLocking Glasses and Insomnia
hechter, A., Kim, E. W., St-Onge, M. P., & Westwood, A. J. (2018). Blocking nocturnal blue light for insomnia: A randomized controlled trial. Journal of Psychiatric Research, 96, 196-202.
This study investigated the effects of wearing amber-tinted blue light-blocking lenses before bedtime on sleep in individuals with insomnia. Results indicated significant improvements in sleep quality compared to clear lenses.
Esaki, Y., Kitajima, T., Takeuchi, I., Tsuboi, S., Furukawa, O., Moriwaki, M., Fujita, K., & Iwata, N. (2017). Effect of blue-blocking glasses in major depressive disorder with sleep onset insomnia: A randomized, double-blind, placebo-controlled study. Chronobiology International, 34(6), 753-761.
This randomized controlled trial examined the impact of blue-blocking glasses on sleep onset insomnia in patients with major depressive disorder. The findings suggested that blue-blocking glasses improved sleep quality in this population.
Liset, R., Grønli, J., Henriksen, R. E., Henriksen, T. E. G., Nilsen, R. M., & Pallesen, S. (2022). A randomized controlled trial on the effects of blue-blocking glasses compared to partial blue-blockers on sleep outcomes in the third trimester of pregnancy. PLoS ONE, 17(1), e0262799.
This study assessed the effectiveness of blue-blocking glasses on sleep outcomes in pregnant women during their third trimester. The results indicated improvements in sleep quality among participants using blue-blocking glasses.
Esaki, Y., Kitajima, T., Takeuchi, I., Tsuboi, S., Furukawa, O., Moriwaki, M., Fujita, K., & Iwata, N. (2016). Effect of blue-blocking glasses on sleep and circadian rhythm in patients with delayed sleep phase disorder: A randomized controlled trial. Sleep Medicine, 24, 93-97.
This randomized controlled trial explored the effects of blue-blocking glasses on sleep and circadian rhythm in patients with delayed sleep phase disorder. The study found that the glasses were effective in advancing sleep onset and improving sleep quality.
van der Lely, S., Frey, S., Garbazza, C., Wirz-Justice, A., Jenni, O. G., Steiner, R., Wolf, S., Cajochen, C., & Bromundt, V. (2015). Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers. Journal of Adolescent Health, 56(1), 113-119.
This study investigated the use of blue-blocker glasses to counteract the alerting effects of evening LED screen exposure in male teenagers. The findings suggested that the glasses could mitigate the negative impact of screen exposure on sleep.
Sleep Masks
1. Sleep Masks Improve Memory & Alertness (2022)
Wearing an eye mask during overnight sleep improves episodic learning and alertness
Citation (APA):
Toffoli, A., Sowman, P. F., McFadyen, J., & Thompson, J. C. (2022). Wearing an eye mask during overnight sleep improves episodic learning and alertness. Sleep, 45(8), zsac089. https://doi.org/10.1093/sleep/zsac089
2. ICU Meta-Analysis: Sleep Masks Improve Sleep Quality
The effectiveness of eye masks and earplugs for sleep promotion in critically ill patients: A systematic review and meta-analysis
Citation (APA):
Hu, R. F., Jiang, X. Y., Zeng, Y. M., Chen, X. Y., & Zhang, Y. H. (2010). The effectiveness of earplugs and eye masks for sleep promotion in critically ill patients: A systematic review and meta-analysis. Critical Care, 14(2), R66. https://doi.org/10.1186/cc8950
3. Cardiac Care Sleep Study
Effects of eye mask and earplugs on sleep quality in cardiac patients: A randomized controlled trial
Citation (APA):
Demir, Y., & Orhan, F. (2011). Effects of earplugs and eye masks on sleep quality in intensive care patients: A randomized controlled trial. Pain Management Nursing, 12(3), 173–179. https://doi.org/10.1016/j.pmn.2009.09.001
4. Ambient Light & Melatonin Suppression
Light exposure at night and its impact on human circadian rhythms and sleep
Citation (APA):
Cajochen, C. (2007). Alerting effects of light. Sleep Medicine Reviews, 11(6), 453–464. https://doi.org/10.1016/j.smrv.2007.07.009