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Optometry research finds blue light causes sleep blues

Blue light from smartphones and other devices is thought to trick the brain into thinking it is still daytime at night, causing melatonin release and reducing sleep quality. | Thom Dwyer/The Cougar

Technology is essential to student life — it is used for studying, communication, entertainment and more. Those long hours of staring at a screen, however, can lead to potential consequences.

A new study by the University of Houston College of Optometry has shown that blue light emitted from technological devices is the cause of sleep deprivation in people who stare at their screens right before bed.

Assistant professor Lisa Ostrin, the leader of the study, said their hypothesis was that the blue light emitted from electronic devices is suppressing melatonin release at night and reducing sleep quality.

“There’s a lot of evidence already that artificial light disrupts sleep patterns and sleep quality,” Ostrin said. “We wanted to use some new objective methods to test sleep quality and melatonin level, and also assess whether it was mediated by this new photoreceptor that’s been recently characterized in the eye.”

Ostrin said the effect of blue light on an individual’s sleep patterns is caused by one of the three photoreceptors of the eye called the intrinsically photosensitive retinal ganglion cells, shortened to ipRGCs. Ostrin and two other researchers conducted a three-week study using a group of participants to discover how this cell related to sleep.

The group of participants were told to carry on with their daily routine wearing a wrist-worn activity and sleep monitor for the three weeks. For the final two weeks, they put on blue-light-blocking glasses for about three hours before they slept.

“Over the last 10 years or so, we’re beginning to learn the role of the ipRGC’s,” Ostrin said.  “Its job is really to detect light and darkness and tell our body when it’s day and night, so those particular photoreceptors that are getting too much light input at night.”

The glasses, also called “blue blockers” or amber-tinted lenses, block the blue light wavelengths from affecting the eyes.

“We believed that would essentially trick our eyes into thinking it’s nighttime and help release melatonin and then prepare our bodies for sleep,” Ostrin said. “With increased melatonin, it should improve our sleep quality and help us feel more alert and awake the next day.”

One of the researchers in the study, Kaleb Abbot, said that they had the subjects fill out a survey after the two weeks of wearing blue blockers to find out their results.

“Our were results were pretty incredible and very fascinating,” Abbot said. “We found that our subjects actually increased their sleep duration by 24 minutes at night on average, and that was measured through the smart watch we had them wear.”

Abbot said they also found that 21 out of the 22 participants felt that their sleeping was improved after wearing the blue-blocker glasses, and that they were more awake and alert throughout the day.

Although the blue-blocking glasses are the most effective in improving sleep quality, Ostrin said that the using the nighttime mode on smart phones and computers are a great start.

“The reason is because not only do we get lights from our devices, but even the room lights have quite a bit of blue light in them that’s tricking our bodies into thinking it’s still daytime,” Ostrin said. “So by wearing the glasses you can block a higher percentage of those wavelengths.”

Ostrin said the blue blocker glasses used in the study are about $10 on Amazon and block about 98 percent of the blue wavelengths.

Ph.D. candidate in biomedical engineering Gwen Musial, also a participant in other studies performed by the College of Optometry, said she uses several blue-blocking apps and nighttime modes on her phone.

“I have noticed that when my phone is less dim with the blue blocking on, I just use my phone less, and I think that has been, in general helping, my sleep pattern,” Musial said.

Musial said she recommends the apps because they are simple and free.

Ostrin said that lack of sleep has been linked several health problems, so it is important for people to find ways to have regular sleep periods at night.

“One thing that I think is really important for students is that we hear a lot that we should turn off our devices and turn down the lights before bedtime, but that’s our most productive time, especially if students are studying,” Ostrin said.  “So if they do something like wear blue blockers, then it should improve their sleep quality and allow melatonin to be released in a more normal fashion.”

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