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Blue Blocking Glasses for Everyone!
The Importance of Blocking Artificial Light at Night
People often ask "When should I wear blue blocking glasses? Should I wear them at all?" Let’s dive into the reasons to use blue blockers, and how to use them.
The Impact of Blue Light
The blue light that is given off by computers, electric lights, and handheld devices is a shorter wavelength that's more prevalent in morning sunlight. As the day progresses, natural sunlight shifts from white light (which includes blue), to the longer wavelengths of yellow and red light. Human beings historically have not been exposed to blue light in the evening. Prior to electric light people were in sunset or darkness, candle or firelight, which all give yellow-red light, a longer wavelength. In natural conditions, our melatonin levels can start to rise in the evening, causing us to become drowsy and fall asleep.
Blue light signals to our body "time to wake up, time to be alert" and suppresses melatonin. That is part of the reason people now are just not feeling as sleepy at bedtime. It’s important to note that children are much more sensitive to the melatonin suppressing effects of blue light at night. Keep in mind that lower levels of light that adults are insensitive to, may be enough to disturb a child’s sleep. Blue light blocking glasses are well-researched for several types of sleep complaints. They help people who have insomnia, those who have delayed sleep-wake phase disorder, and children. They can also be helpful for jet lag or shift workers.
Delayed Sleep-Wake Phase Disorder
In delayed sleep-wake phase (DSWP), people don’t fall asleep until much later than social norms. They often don’t fall asleep until sometime between 1a-6a, and therefore need to sleep later in the morning in order to get the sleep they need. This is a challenge, as lifestyle demands often require rising before they’ve gotten enough sleep. Yet going to bed early doesn’t work, as they are just not sleepy, and unable to fall asleep any earlier than they currently do. For this reason, people with DSWP are often chronically sleep deprived. A recent study found that when people with Delayed Sleep-Wake Phase wore blue blocking glasses from 9pm until bedtime for just 2 weeks, their melatonin rose earlier. Likewise, they were able to fall asleep about two hours earlier each night. This is a huge win, resulting in more sleep and less likelihood of chronic sleep deprivation and all its’ negative effects.
Evening Light Recommendations
Given how 80% of people are living under artificial light at night, blue blockers are probably healthful for most people. The light recommendations released in 2022 for sleep and circadian health include 10 lux or less, without blue light, for 3 hours before bed. For many people this is just not realistic, as we are still in the active part of our day, using electronic devices in homes that are brightly lit. Melatonin has a role not only in sleep and circadian health, but beyond sleep too. This is another reason we want to create conditions that allow optimal melatonin levels during times it is dark outside. (More on melatonin’s actions throughout the body in another newsletter).
1. When choosing blue blocking glasses, there are several considerations. Ensure that the glasses have an orangish tint. Some companies sell blue blocking glasses with a light blue tint, which are less effective. A clear-looking lens is also likely not as effective. Orange-tinted lenses block the most blue light and at the same time allow beneficial, non-circadian, wavelengths to get through to your eye.
2. Don’t wear blue blocking glasses all day, because you need that blue light to signal that it is time to be active, particularly in the morning. People who work on the computer for extended periods may have blue blocking lenses to protect their eyes. If you do, remember to take them off when you go outside or do other tasks.
3. Wear the blue blocking glasses for the 2-3 hours before bed. Setting a phone alarm for that time can help you get into the habit, it’s what we do here at our home.
4. Have a pair for everyone in the family, particularly children if they use electronics in the hours before bed.
5. Shift workers can use them also in the time before bed to improve sleep, though they should not be worn driving if visibility is impaired by them.
Blue blocking glasses are an essential part of the sleep tool kit, I hope you have the opportunity to try some for a couple weeks and see what a difference it makes for your sleep and circadian health!
Sleep well and dream big,
Dr. Catherine Darley
1. Mason BJ, et al. Spectrophotometric properties of commercially available blue blockers across multiple lighting conditions. Chronobiol Int. 2022 May;39(5):653-664..
2. Esaki Y, et al. Wearing blue light-blocking glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: An open-label trial. Chronobiol Int. 2016;33(8):1037-44.
3. Meléndez-Fernández OH, et al. Circadian Rhythms Disrupted by Light at Night and Mistimed Food Intake Alter Hormonal Rhythms and Metabolism. Int J Mol Sci. 2023 Feb 8;24(4):3392.
4. Hester L, et al. Evening wear of blue-blocking glasses for sleep and mood disorders: a systematic review. Chronobiol Int. 2021 Oct;38(10):1375-1383.
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