Interventions to reduce short-wavelength (“blue”) light exposure at night and their effects on sleep: A systematic review and meta-analysis

Abstract

The sleep-wake and circadian cycles are influenced by light, particularly in the short-wavelength portion of the visible spectrum. Most personal light-emitting electronic devices are enriched in this so-called “blue” light. Exposure to these devices in the evening can disturb sleep. Interventions to reduce short-wavelength light exposure before bedtime may reduce adverse effects on sleep. We conducted a systematic review and meta-analysis to examine the effect of wearing color-tinted lenses (e.g., orange or amber) in frames to filter short-wavelength light exposure to the eye before nocturnal sleep. Outcomes were self-reported or objective measures of nocturnal sleep. Relatively few (k=12) studies have been done. Study findings were inconsistent, with some showing benefit and others showing no effect of intervention. Meta-analyses yielded a small-to-medium magnitude combined effect size for sleep efficiency (Hedge’s g=0.31; 95% CI: -0.05, 0.66; I2=38.16%; k=7), and a small-to-medium combined effect size for total sleep time (Hedge’s g=0.32; 95% CI: 0.01, 0.63; I2=12.07%; k=6). For self-report measures, meta-analysis yielded a large magnitude combined effects size for Pittsburgh Sleep Quality Index ratings (Hedge’s g=-1.25; 95% CI: -2.39, -0.11; I2=36.35%; k=3) and a medium combined effect size for total sleep time (Hedge’s g=0.51; 95% CI: 0.18, 0.84; I2=0%; k=3), Overall, there is some, albeit mixed, evidence that this approach can improve sleep, particularly in individuals with insomnia, bipolar disorder, delayed sleep phase syndrome, or attention-deficit hyperactive disorder. Considering the ubiquitousness of short-wavelength-enriched light sources, future controlled studies to examine the efficacy of this approach to improve sleep are warranted.

A randomized controlled trial on the effect of blue-blocking glasses compared to partial blue-blockers on melatonin profile among nulliparous women in third trimester of the pregnancy

“…The frequency of side-effects is in line with what was reported by Henriksen ( Henriksen et al, 2016 ), while other studies have reported no side effects ( Burkhart and Phelps, 2009 ). These findings are consistent with the previous conclusions from the literature that BB-glasses are a safe intervention when used in the evening and night ( Esaki et al, 2017 ; Henriksen et al, 2016 ; Shechter et al, 2020 ). The side effects in five of the six cases disappeared with further use.…”

Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health: guidance from the American Academy of Sleep Medicine and the Sleep Research Society

“…This approach to shift work adaptation would therefore only work well for fixed or slowly rotating shift schedules, in which shift start or end times are expected to occur at approximately the same time for several consecutive days. Even then, additional measures may be required, such as wearing dark goggles or using technological solutions to reduce bright or blue light exposure at certain times, 215 making the desired effect difficult to achieve. 216 Strategies for mitigating risks in shift workers that rely on minimization of extended wakefulness and sleep loss, rather than shifting the biological clock, may be more effective in practice.…”

Sleep and circadian rhythms: pillars of health—a Keystone Symposia report

“…3). Comparatively larger effects were seen for subjective measures of sleep, with medium‐to‐large combined effect sizes observed for Pittsburgh Sleep Quality Index ratings and self‐reported total sleep time 83 . Overall, there is some modest evidence that this approach can be beneficial for nocturnal sleep, particularly in individuals with sleep disturbances (e.g., insomnia symptoms and delayed sleep phase syndrome) or psychiatric conditions (e.g., bipolar disorder and attention‐deficit hyperactive disorder).…”