Posted by Su Lee

With increasing use of technology in the form of digital devices, an average adult spends as high as 12 hours per day in front of screens1. Digital devices such as computer, television, mobile phone, and tablet emit blue light which causes strain to our eyes, disrupt sleep cycles, and—in the long run—negatively impacts our vision. Those exposed to blue light on a daily basis for long hours can use blue light blocking glasses to prevent the ill-effects. We sat down with Alena Reznik, MD at CHA HPMC’s Southern California Eye Institute to understand the impact of blue light and benefit of using blue light blocking glasses.

What are the benefits of wearing blue light blocking glasses?

We get constant exposure to blue light from ambient sunlight, computer screens, tablets, and mobile phones. The brain associates blue light as daytime. If a person is exposed to blue light for long periods of time during the night, the light makes it more difficult for to fall asleep at night and wake up in the morning. By wearing blue light blocking glasses, we can prevent our bodies from changing—on exposure to blue light—and impacting our sleep schedule.

Does blocking blue light prevent eye strain?

Eye strain is related to looking and focusing at a screen that is close to the eyes for an extended period of time. The symptoms of eye strain are not related to exposure to blue light from computer screens, tablets, or mobile phones.

Eye strain can be resolved by taking breaks from staring at computer screens, tablets, or mobile phones for long periods of time and focusing on objects in the distance. For instance, you can engage in outdoor activities during the break. The eye strain can be reduced by regularly looking away from computer screens, tablets, or mobile phones every 20 minutes and focusing on objects at least 20 feet away for at least 20 seconds or more. If looking away does not help, then one should use artificial tears to help with the dryness of the eyes.

What is the relationship between blue light and melatonin levels?

There are studies that show relationship between blue light and melatonin levels. Any type of light can suppress the secretion of melatonin and research suggests that blue light—at night—does so more powerfully. Blue light exposure at night suppresses the secretion of melatonin, a hormone that influences our body’s circadian rhythms—natural internal body process which regulates our sleep-wake cycle every 24 hours—that may lower melatonin levels.


1Fisher, Nicole. How Much Time Americans Spend In Front Of Screens Will Terrify You. Forbes. Published [January 24, 2019]. Accessed [July 19, 2019].

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