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.