A new study has added weight to the argument that blue light emitted from digital devices can disrupt sleep patterns.
The study, by researchers at the University of Houston College of Optometry, published in Ophthalmic & Physiological Optics, found that blue light emitted from these devices could contribute to the high prevalence of reported sleep dysfunction.
Study participants, ages 17–42, wore short wavelength-blocking glasses three hours before bedtime for two weeks, while still performing their nightly digital routine. Results showed about a 58 per cent increase in their night-time melatonin levels, the chemical that signals your body that it’s time to sleep – levels that are even higher than increases from over-thecounter melatonin supplements, according to Dr. Lisa Ostrin, assistant professor at the UH College of Optometry.
“The most important takeaway is that blue light at night time really does decrease sleep quality. Sleep is very important for the regeneration of many functions in our body,” said Dr. Ostrin.
Dr. Ostrin recommended limiting screen time, applying screen filters, wearing computer glasses that block blue light, or using anti-reflective lenses to offset the effects of artificial light at night-time
Wearing activity and sleep monitors 24 hours a day, the 22 study participants also reported sleeping better, falling asleep faster, and even increased their sleep duration by 24 minutes a night, according to Dr. Ostrin.
The largest source of blue light is sunlight, but it’s also found in most LED-based devices. Blue light boosts alertness and regulates our internal body clock, or circadian rhythm, that tells our bodies when to sleep. This artificial light activates photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGCs), which suppresses melatonin.
Dr. Ostrin recommended limiting screen time, applying screen filters, wearing computer glasses that block blue light, or using anti-reflective lenses to offset the effects of artificial light at night-time. Some devices even include night mode settings that limit blue light exposure.
“By using blue blocking glasses we are decreasing input to the photoreceptors, so we can improve sleep and still continue to use our devices. That’s nice, because we can still be productive at night,” she said.