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Updated: Aug 18, 2021

By: Kylie Thompson, BS, CPT, LMT

What do you do before you go to bed? Most often, I find the answer revolves around checking email, mindlessly scrolling on social media, and watching television. This late night screen time could be costing you a great night’s sleep. The culprit causing your sleep to suffer may be the blue light emitted from the device you are using to read this article.

In order to understand what blue light can do to our eyes and body, we need to know what blue light is. The human eye is only sensitive to the visible light spectrum. The light, formed from electromagnetic particles, travels in waves and is seen as colors: red, orange, yellow, green, blue, indigo, and violet. Each color varies in wavelength and energy with an inverse relationship between the two. Light that has a short wavelength contains more energy and long wavelengths have less energy. Blue light is one of the shortest, highest-energy wavelengths with red light on the opposite end of the spectrum. The high energy waves penetrate the eye’s retina deeper than other wavelengths making our eyes more sensitive to blue light.

Sunlight, digital screens, LED lighting, and electronic devices are included as sources of blue light and are found everywhere in our lives. All of this light affects the body’s biological sleep-wake cycle, or circadian rhythm, positively and negatively. Natural and artificial blue light has been shown to elevate mood, cognitive functions, and alertness during the daytime.1  Your eyes detect the change from light to dark and send a signal to the brain to release the hormone melatonin that slowly causes you to feel sleepy. Continuing to expose the eyes to the artificial blue light into the evening tricks your brain into staying in the active state and suppressing the production of melatonin. The most common symptoms for low melatonin are feeling awake around 10 pm, low immunity, tiredness during the day, and finding it hard to fall asleep. These symptoms increase your risk for chronic illness and diseases, such as heart disease, depression, obesity, and diabetes.1

There are practical ways to decrease blue light exposure in your life. It is recommended to minimize screen time in the two to three hours before bedtime and dim your lights beginning at sunset.2  This includes dimming the brightness or putting down electronic devices. However, if you are unable to step away from your device, there are ways to help your eyes filter blue light. Newer cell phones, tablets, and computers have a blue light or nighttime filter setting built into the device. Check your device in your Settings and then Display to see if there is an option. Also, free applications are accessible in Apple’s App Store and Android’s Play Store for those that do not have a filter built in. Screen protectors or covers are available for your computer monitor, phone, tablet, and laptop through Amazon and Eyesafe. There are orange-tinted glasses designed to block blue light waves. Amazon has a great selection of glasses, including the brands Eyesafe and Cyxus. If you prefer to try before you buy, most eyewear and optical chains, like LensCrafters, carry these glasses.

The road to quality sleep can be a difficult one and will require patience and persistence, as the change will not happen overnight. The first step is easier said than done when it comes to disconnecting our eyes from our devices before bed. If you follow some of these tips and find you are still having trouble sleeping, there may be more going on than meets the eye. I encourage you to talk with your doctor to dig deeper and get a better understanding of why you are awake. Sleep is the golden chain that ties health and our bodies together. — Thomas Dekker

  1. Harvard Health Publishing. (2018, August 13). Blue light has a dark side. Retrieved from

  2. Vimont, C. (2018, October 18). Should You Be Worried About Blue Light? Retrieved from

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