Blue Light And Sleep: Are Smartphones Giving You Insomnia?


Since getting an iPad Pro, I’ve noticed that I’m reading a lot before bedtime on it. I also have a Kindle paper white, which supposedly doesn’t produce light in the High-energy visible light band.

So I’ve been wondering if my sleep is being affected. Because it seems like I’m waking up a lot more during the night, whereas I used to sleep straight through.

Time to do a little digging.

Scientists have known for years that certain wavelengths of light in certain doses can heal, but it seems they are finding that it can also harm.

High-energy visible light is high-frequency, high-energy light in the blue band from 400 to 500 nm in the visible spectrum. HEV blue light has been implicated as a cause of age-related macular degeneration, weight gain, and sleep loss.

What is Blue Light?

All light is made up of electromagnetic particles traveling in waves. Blue light has a wavelength of between around 380nm and 500nm. This makes blue light one of the shortest, highest-energy wavelengths.

The majority of modern electronic devices use Light Emitting Diode (LED) back-light technology to help heighten screen clarity and brightness.  These LEDs emit very strong blue light waves.

Cell phones, computers, tablets and flat-screen televisions are just among a few of the devices that use this technology. And they are becoming more and more a part of our lives.

According to a 2011 poll by the National Sleep Foundation, 90 percent of Americans use some kind of electronic device within the hour before bed.

A 2014 poll by researchers at the U.S. Centers for Disease Control and Prevention found that 74% of teens aged 12-17 access the internet on cell phones, tablets, and other mobile devices at least occasionally.

Children and teenagers (ages 8-18) spend more than 7 hours a day consuming electronic media, according to a study by the Kaiser family Foundation. Prior to age 10, children’s eyes are not fully developed.

The lens and cornea are still mostly transparent and thus overexposed to light, so over exposure to blue light is made worse for these children.

Blue Light Insomnia: Circadian Rhythm Disruptions

You are probably already, or soon will be, part of those statistics. One of the millions of people who keep their smartphone or tablet by your bedside.

Maybe you like to read some news or watch a few videos before falling asleep. You’ve probably even woken up in the middle of the night to check your text messages or Facebook.

If so, you are part of a trend causing concern in the medical community. As the American Medical Association states:

“Exposure to excessive light at night, including extended use of various electronic media, can disrupt sleep or exacerbate sleep disorders, especially in children and adolescents."

Because blue light is especially pronounced in daylight, our bodies link it with daytime. That may be why exposure to blue light can make us more alert and improve our response times, as anyone who has used a light therapy lamp to fight Seasonal Affective Disorder knows.

Blue light also has been shown to suppress melatonin.

Melatonin is a hormone produced by the pineal gland at night and under conditions of darkness in both diurnal and nocturnal species. It is a timing messenger, signaling information needed for circadian rhythms throughout the body.

Researchers at the University of Basel reported In May 2011 that subjects who spent time at night in front of an LED computer screen experienced

“a significant suppression of the evening rise in endogenous melatonin and … sleepiness."

Over the last decade, neuroscientists have discovered unique light-sensitive cells in the eye that detect light. These cells are separate from those we use for vision and contain a photopigment called melanopsin that is particularly sensitive to blue light.

Says Harvard Medical School sleep researcher Steven Lockley, speaking to the Chicago Tribune:

“Blue light preferentially alerts the brain, suppresses the melatonin and shifts your body clock all at the same time. Your brain is more alert now and thinks it’s daytime because we have evolved to only see bright light during the day."

Xue Ming, professor of neuroscience and neurology at Rutgers New Jersey Medical School, in a study on the effects of texting on sleep, found that students who turned off their devices or who messaged for less than 30 minutes after lights out performed significantly better in school than those who messaged for more than 30 minutes after lights out.

The effects of blue light emitted from smartphones and tablets are intensified when viewed in a dark room, Ming says.

A Mayo Clinic study suggests dimming the smartphone or tablet brightness settings and holding the device at least 14 inches from your face while using it will reduce its potential to interfere with melatonin and impede sleep.

And until manufacturers develop more “circadian-friendly” electronic devices that increase or decrease light exposure based on time of day, Mariana Figueiro, associate professor at Rensselaer and director of the LRC’s Light and Health Program, recommends dimming these devices at night as much as possible in order to minimize melatonin suppression, and limiting the amount of time spent using these devices prior to bedtime.

There is also an app called f.lux available for computers and mobile devices that adjusts a display’s color temperature according to location and time of day. The program was designed to reduce eye strain during night-time use and disruption of sleep patterns.

The program is available for Microsoft Windows, OS X and Linux. It is also available for iOS devices, although it requires the device to be jailbroken.

Digital Eyestrain Syndrome

Symptoms of digital eyestrain, also known as computer vision syndrome, include headaches, blurred vision, neck pain, redness in the eyes, fatigue, eye strain, dry eyes, irritated eyes, double vision, vertigo/dizziness, polyopia, and difficulty refocusing the eyes.

Digital eyestrain has even surpassed carpal-tunnel syndrome as the number one computer-related complaint.

If you spend a lot of time at the computer or focusing on any one thing, you sometimes forget to blink and your eyes can get fatigued.

One of the common recommendations for fighting digital eye strain is to use the the “20 20 20 rule”: every 20 mins, focus the eyes on an object 20 feet away for 20 seconds. This can help reduce eyestrain.

Some ophthalmologists and researchers also recommend eyes glasses with blue blocking filter coating to help mitigate the adverse effects.

I will be following the above suggestions from now on, to see if they are effective.

For More Information:

No Phones In Bed. The Atlantic, Dec 22, 2014

Blue light has a dark side. Harvard health publications

Health Effects of Artificial Light. Scientific Committee on Emerging and Newly Identified Health Risks.

DigitEYEzed: The Daily Impact of Digital Screens on the eye health of Americans. The vision council (2013)

Reddy, Chandrasekhara; Low (2013). Computer vision syndrome: a study of knowledge and practices in university students. Neoalese Journal of Ophthalmology 5 (2).

Kids Still Getting Too Much ‘Screen Time’: CDC.

Teens and Technology 2013. Pew Research Center.

New Molecular Insight on How the Eye Processes Light