Blue Blockers at Night and Insomnia Symptoms

Under entrained conditions, humans maintain a consolidated nocturnal sleep episode that coincides with environmental darkness and endogenous melatonin secretion. Various factors, such as artificial light, can compromise this temporal harmony, resulting in sleep disruption. Light is the strongest synchronizer of the circadian clock, with direct inputs via the retinohypothalamic tract to brain centers regulating sleep and circadian rhythms. Evening light exposure can suppress melatonin secretion and worsen sleep. This is critical, since most individuals routinely expose themselves to light before bedtime. The high sensitivity of the circadian system to blue wavelength light indicates that modern light sources such as light-emitting diodes (LED) may have particularly deleterious effects on sleep. It is possible to selectively filter out blue light while maintaining other visible spectra with blue-blocking (BB) lenses. Wearing BB lenses before bedtime may present a simple, affordable, and safe method to improve sleep. None have yet investigated the effects of BB lenses on subjective and objective sleep in insomnia patients, while simultaneously exploring the effects on melatonin secretion.

This study seeks to investigate the impact of BB lenses on melatonin and sleep in insomnia patients using a randomized, placebo-controlled crossover study, with the aim of developing a novel non-pharmacological approach for the treatment of insomnia. 15 individuals with insomnia will wear either BB or placebo (clear) lenses for 2 hours preceding bedtime while at home, for 1 week in a cross-over design. Sleep quality will be documented while at home, at also melatonin secretion while in the laboratory. It is predicted that compared to placebo, wearing BB lenses for 2 hours preceding bedtime will attenuate bright light associated melatonin suppression and improve sleep.

Pittsburgh Insomnia Rating Scale-65; measures the self-reported severity of insomnia over the past week. Higher scores indicate worsened severity. There are 65 items, each scored on a 4-point scale from low-high on symptom severity or frequency. There is a Total score, and 3 subscales: Distress score (how bothersome the sleep impairment is), Sleep Parameters score (sleep quality), and Quality of Life score. For the total score scoring is done by summing the scores from questions 1-65. Minimum Score=0 (good); Maximum Score=195 (bad) For the distress score, scoring is done by summing the scores from questions 1-46. Minimum Score=0 (not bothered); Maximum Score=138 (severely bothered) For the sleep parameters score, scoring is done by summing the scores from questions 47-56. Minimum Score=0 (good sleep); Maximum Score=30 (disrupted sleep) For the quality of life score, scoring is done by summing the scores from questions 57-65. Minimum Score=0 (excellent); Maximum Score=27 (poor)

Pittsburgh Insomnia Rating Scale-65; measures the self-reported severity of insomnia over the past week. Higher scores indicate worsened severity. There are 65 items, each scored on a 4-point scale from low-high on symptom severity or frequency. There is a Total score, and 3 subscales: Distress score (how bothersome the sleep impairment is), Sleep Parameters score (sleep quality), and Quality of Life score. For the total score scoring is done by summing the scores from questions 1-65. Minimum Score=0 (good); Maximum Score=195 (bad) For the distress score, scoring is done by summing the scores from questions 1-46. Minimum Score=0 (not bothered); Maximum Score=138 (severely bothered) For the sleep parameters score, scoring is done by summing the scores from questions 47-56. Minimum Score=0 (good sleep); Maximum Score=30 (disrupted sleep) For the quality of life score, scoring is done by summing the scores from questions 57-65. Minimum Score=0 (excellent); Maximum Score=27 (poor)

Sleep Efficiency (Time Spent Asleep Divided by Total Time in Bed) Determined With Wrist-worn Accelerometry

Wrist-worn accelerometry gives an estimate of time spent asleep, time spent in bed, and sleep efficiency can be calculated from this. Sleep efficiency is calculated as time spent asleep divided by total time in bed. Here, we considered the mean calculated sleep efficiency over each 7-day treatment period.

Sleep Efficiency (Time Spent Asleep Divided by Total Time in Bed) Determined With Wrist-worn Accelerometry

Wrist-worn accelerometry gives an estimate of time spent asleep, time spent in bed, and sleep efficiency can be calculated from this. Sleep efficiency is calculated as time spent asleep divided by total time in bed. Here, we considered the mean calculated sleep efficiency over each 7-day treatment period.

Inclusion Criteria: Insomnia for at least 1 month based on Insomnia Symptoms Questionnaire Exclusion Criteria: obstructive sleep apnea; narcolepsy; periodic leg movement disorder currently shift worker psychiatric or neurologic disorders deep vein thrombosis current cigarette smoker currently taking beta-blockers pregnant/breastfeeding children less than 1 year old at home excessive daily caffeine intake

Shechter A, Kim EW, St-Onge MP, Westwood AJ. Blocking nocturnal blue light for insomnia: A randomized controlled trial. J Psychiatr Res. 2018 Jan;96:196-202. doi: 10.1016/j.jpsychires.2017.10.015. Epub 2017 Oct 21.

Shechter A, Westwood AJ. A behavioral intervention for insomnia improves blood pressure. Sleep Med. 2017 Sep;37:225. doi: 10.1016/j.sleep.2017.07.003. Epub 2017 Jul 15. No abstract available.