- Smartphones, tablets and other electronic devices that are lit by the LEDs, can have a peak wavelength at the blue portion of the screen spectrum
- By the use of blue light emitting electronic devices, melatonin an sleep inducing hormone is suppressed at night
- Amber tinted glasses designed to block the blue light may now prevent insomnia
The use of amber-tinted blue light blocking glasses may provide relief for insomnia patients. Bedtime use of light-emitting electronic devices can contribute to a wide variety of sleep problems. The findings of this study are further discussed in the Journal of Psychiatric Research
Smartphones, tablets and other light-emitting devices are lit by LEDs, which have a peak wavelength in the blue portion of the spectrum. Blue light at night suppresses melatonin and increases alertness; the use of amber-tinted lenses that block blue light mitigates these effects.
‘Amber lenses can be considered as a safe, affordable and easily adoptable behavioral intervention for insomnia symptoms.’
The Columbia team, led by Ari Shechter, Ph.D., assistant professor of medical sciences, reasoned that selectively blocking blue light in the hours before bedtime would lead to improved sleep in individuals with insomnia.
To test their theory, the researchers recruited 14 individuals with an insomnia diagnosis to take part in a small study. For seven consecutive nights, participants wore wrap-around frames with amber-tinted lenses that blocked blue light or with clear placebo lenses for two hours before bedtime. Four weeks later, participants repeated the protocol with the other set of glasses.
The researchers found that participants got around 30 minutes extra sleep when they wore the amber lenses compared to the clear lenses. In self-reported sleep surveys, participants also reported greater duration, quality, and soundness of sleep, and an overall reduction in insomnia severity.
These findings are consistent with prior studies showing a benefit of blue-light-blocking lenses in improving sleep, but should be replicated in larger controlled studies, Shechter said.
"Now more than ever we are exposing ourselves to high amounts of blue light before bedtime, which may contribute to or exacerbate sleep problems," Shechter said. "Amber lenses are affordable, and they can easily be combined with other established cognitive and behavioral techniques for insomnia management."
Many smartphones screens can now be adjusted to emit amber instead of blue light, and Shechter said these settings should help to improve sleep. "I do recommend using the amber setting on smartphones at night, in addition to manually reducing the brightness levels. But blue light does not only come from our phones. It is emitted from televisions, computers, and importantly, from many light bulbs and other LED light sources that are increasingly used in our homes because they are energy-efficient and cost-effective," he said.
"The glasses approach allows us to filter out blue-wavelength light from all these sources, which might be particularly useful for individuals with sleep difficulties."
The use of amber lenses also appeared to reduce blood pressure in the study's participants (these data are published in the September issue of Sleep Medicine). "Insomnia is often characterized by physiologic hyperarousal, which may account for the relationship between poor sleep and cardiovascular risk," Dr. Shechter explained. "Going forward, it will be interesting to examine whether this blue-light blocking approach can be useful for improving cardiovascular outcomes like hypertension in individuals with poor sleep."
- Elijah Wookhyun Kim, Marie-Pierre St-Onge, and Andrew J. Westwood . Blocking nocturnal blue light for insomnia: A randomized controlled trial, Journal of Psychiatric Research (2017).https://doi.org/10.1016/j.jpsychires.2017.10.015