Photo: Elizabeth Conley, Staff

The Night Shift feature in Apple's iOS operating system for iPhones and iPads filters out the display's blue light during hours the user specifies. The company says this can lead to better sleep.

The Night Shift feature in Apple's iOS operating system for iPhones and iPads filters out the display's blue light during hours the user specifies. The company says this can lead to better sleep.

The glow of technology has a dark side

The reason your smartphone, laptop, flat screen or any manner of electronic gadgetry keeps you up nights may not be what you think.

Obsessive surfing, scrolling and binge watching doesn't help. But the larger culprit is the bright blue glow cutting through the darkness and tricking the brain into thinking it is daytime, scientists have figured out in recent years.

Just how much all this personal technology messes with sleep was a question a team of University of Houston researchers set out two years ago to find out.

"We believed that blocking blue light would improve sleep quality and duration" said Lisa Ostrin, lead researcher and an assistant professor at the UH College of Optometry.

They weren't prepared for the magnitude of their finding.

Just by slapping on a pair of cheap orange sunglasses a few hours before bedtime while still using their regular devices, study participants' melatonin levels shot up by 58 percent. Melatonin is the hormone released by the pineal gland in the brain that signals it's time to sleep.

In addition, by simply shifting the visual hue from blue to orange (think sunset) the group reported drifting off earlier and more easily, plus staying asleep longer. Most added about a half-hour to their sleep total, one volunteer caught an extra hour and a half.

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For a nation where reportedly one in three are sleep deprived, that just might sound like heaven.

The UH project was completed in early 2016 and its findings were published in June in Ophthalmic & Physiological Optics, the national medical journal of the college of optometrists.

Twenty-one volunteer participants, ages 18 to 40, pledged they would wear the tinted glasses - safety glasses bought at Walmart for about $10 - for two weeks during the hours leading up to bed. Most importantly they would continue usual routines of reading phones or tablets, watching television or working on computers while wearing the glasses.

They also wore specialized smart watches to bed to monitor sleep duration and patterns. While some similar studies have been conducted in sleep labs, Ostrin said she wanted hers to more closely replicate the way people live. Each night and again in the morning the participants underwent saliva swabs to measure melatonin levels.

"I've had poor sleep quality since I was a teenager," said Krista Beach, a 38-year-old post-doctoral student who signed up for the study. She said by wearing the glasses she was able to fall asleep earlier. Even now if she is worried about getting enough sleep before a big day she will grab the glasses.

"Yes, you look kind of funny," she admitted. The biggest cringe-worthy moment was when she showed up at a night performance at the Houston Shakespeare Festival sporting them. In the end she found herself getting sleepier earlier, which meant she slept more.

While it is now understood in scientific circles that there is a link between blue-wavelength light and sleep disruption, Ostrin said she wanted to objectively quantify it. She also wanted to explore the "how" behind this modern-day sleep-tech conundrum.

One of the answers lies in the recent discovery of a third sensory element in the eyes, beyond the more well-known rods and cones. Cones control the ability to distinguish colors, while rods are used for night vision, motion detection and peripheral vision.

The third sensor, called intrinsically photosensitive retinal ganglion cells, signals light changes. It is those sensors that send a message to the brain to start or stop the pineal gland. They have also been found to be the most sensitive to blue light.

"It is very unnatural to receive any blue light at night," explained Kaleb Abbott, one of the study co-authors.

So it stood to reason that exposure to blue light would disrupt the natural order of things.

The UH researchers pondered how they could reset the body's sleep clock.

"It's not like we're all going to turn off our computers and go to bed at 8 o'clock," Ostrin said.

One of the great ironies of unintended consequences is that just about the time one group of scientists was figuring out the third sensor in the retina that cued sleep, another group was paving the way for the tech explosion.

Although most personal device screens may appear white, they are usually illuminated with blue LED lights, which were found to be more energy efficient and easier to see.

A breakthrough to help people work better and longer also worsened their sleep, Ostrin said.

The tech world has jumped on the phenomenon lately, offering devices with night-time modes that switch to softer hues with longer wavelengths and a reddish tint. It is a shift the UH researchers predict is coming in the next tech wave.

One complaint, though, is some consumers say the nighttime modes make it harder to read so they give up.

That helps with sleep, too.

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The glow of technology has a dark side - Houston Chronicle