During the daylight hours, we are all exposed to natural blue light emitted from the sun, which helps to boost our energy, mood, and wakefulness. However, many of us spend our late evening hours with one of our electronic devices such as smartphone, tablet, laptop, computer, television, etc. All these devices also emit high energy blue light.

The amount of blue light emitted from our electronic devices is comparatively lower than that emitted by the sun. But the extended use of electronic devices in the night, the duration of our screen time and its long-term effects will lead to high blue light exposure. As you can see from the spectrum below, the emission of short wavelength and high energy blue light is in the range between 400 to 495 nm. However, studies have shown that the blue light emission between 400 to 450 nm at night can cause damages to our sleep-wake cycle (circadian rhythm) and hence affect our health. [1] [2]

Depending on the amount of time we stare at this high energy blue light, the results could be eye discomfort, prematurely-aged eyes, digital eye strain, macular degeneration (death of photoreceptor cells in the retina), retinal cell damage, sleep disorders, blurred vision, headaches, daytime fatigue or may even lead to permanent vision loss. [3] [4]

Studies have shown that the prolonged use of electronic devices and excessive exposure of blue light at night inhibits our pineal gland, a gland located in the center of our brain. This gland is responsible for the production of the sleep-wake hormone melatonin (a chemical which regulates our sleep-wake cycle). The high exposure of blue light during the evening time inhibits our pineal gland and hence suppresses the production of melatonin at night. This will substantially interrupt our circadian rhythm and thereby cause many lifestyle diseases such as cancers, cardiovascular diseases, neurodegenerative disorders, and diabetes_. [5] [6]

These days, our children are more affected to the blue light effects than adults because of the long duration of screen time. Hence, we need to take precaution against the impact of high-intensity blue light emission. Here are some of the recommendations that one can follow to avoid the risks mentioned above:

Recommendations to improve our sleep and health

• Reduce the use of electronic devices before going to bed to get quality sleep and thereby regenerate the functions of our body.
• Use blue light filters to block the significant amount of blue light emission from our electronic devices such as laptop, computer, television, etc.[7]
• Wear blue light blocking glasses or anti-reflective lenses to offset the effects of electronic blue light emission.[8]
• Use “night mode settings” or “blue light shield”, options on our smartphones, tablets, etc. during the night to minimize the blue light exposure.[9] These filters are readily available in modern Android or iOS operating systems.

References

[1] Sarah L. Chellappa et al., Journal of Sleep Research, 22, 2013, 573-580

[2] Jung-Yoon Heo et al., Journal of Psychiatric Research, 87, 2017, 61-70

[3] Kasun Ratnayake et al., Scientific Reports, 8, 2018, 10207

[4] Kurt K. Benke et al., Human and Ecological Risk Assessment: An International Journal, 19, 2013, 916-929

[5] Yvan Touitou et al., Life Sciences, 173, 2017, 94-106

[6] Naja Hulvej Rod et al., PLOS one, 13, 2018, 1-12

[7] Masahlko Ayaki et al., The Journal of Biological and Medical Rhythm Research, 33, 2016, 134-139

[8] Alexandre Sasseville et al., Journal of Pineal Research, 41, 2006, 73-78

[9] Ji Hye Oh et al., Scientific Reports, 5, 2015, 11325