In a world where we spend hours each day looking at various digital screens, most people know how important it is that we protect our vision. However, many don’t understand the risk excessive blue light exposure poses to more than just our vision. Blue light can affect the circadian rhythms of our wake-sleep patterns and reduce the quantity and quality of our sleeping hours.
This is why glasses that block blue light can be a useful tool for people who spend a great deal of time working in front of computer screens, watching television, or using their cell phone.
In this article, you will learn:
- What blue light is
- The benefits of natural blue light
- The downsides of artificial blue light and excessive nighttime blue light
- If you need to wear glasses that block blue light
- What to look for when purchasing blue light glasses
- Why you need both daytime and nighttime blue light glasses
- Some of my personal recommendations for glasses that block blue light
- How to limit your blue light exposure and the harm this exposure causes
What is blue light?
The sun’s rays, which we perceive as white, are actually made of several different colored wavelengths, including red, yellow, orange, green, purple, and blue. The red, yellow, orange wavelengths on the warm end of the spectrum tend to be longer with less energy, while the cooler-toned wavelengths, such as blue and purple, are shorter with higher energy.
Blue light is one such light wavelength. In the past, the sun was our only source of blue light, only available to us during the daytime. In fact, the highly refractive blue light from the sun is the reason why the sky appears blue. Most evenings and nights prior to the advent of electricity were spent in relative darkness. However, in the modern era blue light is everywhere, at all hours of the day and night.
The most common blue light sources in our everyday lives (1) are electronic screens such aslaptop and desktop computers, televisions, cell phones, handheld gaming consoles, and tablets.
Light fixtures, including fluorescent light bulbs, compact fluorescent light (CFL) bulbs, and light emitting diode (LED) bulbs are also sources of blue light.
While there’s no denying the importance of these technological advances in both digital devices and indoor and outdoor lighting, they’ve drastically increased our exposure to blue light during the daytime and at night. (2)
Unfortunately, there’s a strong and growing body of evidence to support the idea that these unnatural levels of blue light exposure can be harmful to health.
Blue light benefits
Natural blue light does offer some benefits, as exposure to it is associated with natural sunlight.
Daytime blue light exposure can regulate your body’s circadian rhythm, ensuring that you’re alert and awake during the daytime and ready for sleep at night. (2) Blue light as experienced in the daytime within visible light synchronizes the human biological master clock in an area of the brain known as the suprachiasmatic nucleus of the hypothalamus to the 24-hour cycle. These short wavelengths, perceived as a blue color, are the strongest synchronizing agent for the entire circadian system that keeps most biological and psychological rhythms internally synchronized.
Natural blue light exposure may also help to promote normal vision, especially in children. Some evidence shows that people who aren’t exposed to adequate levels of blue light may be more likely to have vision problems such as nearsightedness. (3, 4)
Blue light downsides
Unfortunately, the downsides of excessive blue light exposure, particularly nighttime exposure, far outweigh the potential benefits, especially since we’re constantly bombarded with blue light from our devices and light fixtures.
Digital eye strain is a uniquely modern condition brought on by excessive or prolonged time in front of screens, whether for work or leisure. (5) Spending hours in front of a screen with few breaks can make your eyes tired and cause symptoms such as blurred vision, headache, dry eye, or other eye discomfort. (6) Up to ninety percent of all digital device users may be affected by digital eye strain. This can be a particularly difficult issue to deal with if you work at a computer and can’t simply decrease your screen time. (5)
In addition to digital eye strain, excessive blue light exposure may potentially lead to more serious and chronic vision problems. The main issues presented by excessive exposure are cataracts and macular degeneration. (7) Cataracts are cloudy areas in the lens of your eye. They develop slowly and are common in the elderly, but are also one of the leading causes of blindness around the world. Blue light exposure may increase your risk of developing cataracts because of the damage it can cause to your lens, initiating the buildup of proteins that accumulate to form these cloudy spots. In fact, it’s possible that the formation of cataracts is a protective adaptation to prevent further eye damage. This is because cataracts are able to absorb higher amounts of blue light without allowing it to affect other parts of the eye. (7)
Additionally, blue light may hasten the onset of age-related macular degeneration or vision loss. Blue light exposure is widely considered a risk factor for this kind of degeneration. Test tube studies show that aged eye cells may produce higher levels of vascular endothelial growth factor (VEGF), which increases their sensitivity to blue light. This type of light may also trigger mitochondrial dysfunction that leads to the death of healthy eye cells, speeding up the process of vision loss. (8, 9, 10)
What is circadian rhythm?
Your circadian rhythm, or your body’s internal clock, is primarily dictated by your hormone levels, which can shift significantly over the course of the day and into the night. Unfortunately, excessive blue light exposure can alter your body’s melatonin levels, which is a key player in circadian rhythm and sleep patterns. (11, 12)
Natural blue light exposure during the daytime suppresses melatonin levels, keeping you more awake and alert. However, nighttime blue light exposure has the same effect, which can lead to poor sleep and insomnia. (11) A small randomized controlled trial of fourteen people suffering from insomnia found that wearing lenses that block blue light in the two hours preceding bedtime for just 7seven days significantly increased sleep time, along with the quality and soundness of sleep, compared to placebo lenses. (13)
What are blue light glasses and do you need them?
The many downsides of overexposure to blue light make the case for wearing appropriate blue light filter glasses or lenses. Although you may not need them all the time, they’re certainly useful for people who work indoors at computers or other screens. Blue light filter glasses may also be helpful for night shift workers who want to suppress their daytime exposure to blue light so that they can sleep better at night. I also highly recommended using blue light glasses if you’re using any kind of digital screen after dark.
This brief buyer’s guide will help you select the glasses that will best meet your needs in blocking blue light.
These types of glasses are designed to filter out all or part of the blue light you’re exposed to, depending on whether they’re made for day or night use. If you work at a computer, I strongly recommend you at least purchase daytime blue light glasses. These glasses will reduce the amount of blue light you’re exposed to, to normal levels so that you can still get the beneficial, energizing effects of blue light while decreasing your risk of excessive blue light exposure.
If you also spend a great deal of time after dark working on your computer, watching TV, or on your phone, you should consider purchasing nighttime blockers as well. These block all blue light wavelengths, in order to more naturally replicate true nighttime conditions and prevent the suppression of melatonin after dark that can interfere with your circadian rhythm and sleep patterns.
If you work nights, you may want to consider purchasing nighttime blockers to use during the day to help foster better sleep during the period you’re off work.
What to look for
According to Block Blue Light, a brand that I personally trust and recommend, for daytime use you should look for clear-tinted lenses that block between forty and fifty percent of blue light. These provide protection against 450-455 nanometer blue wavelengths that appear to be the most harmful. For nighttime use,orange-tinted lenses block a hundred percent of blue light, while also filtering green light which may also suppress melatonin, up to 550 nm.
These glasses filter out fifty percent of blue light, including the 455 nm wavelength, which is the most harmful and intense type of blue light.
These nighttime blue blockers block a hundred percent of blue and green light, making them ideal for nighttime use to minimize sleep and avoid circadian rhythm disorder.
How to limit blue light exposure and harm
In addition to glasses that block blue light, there are also several other ways you can limit your exposure, particularly at nighttime. Many of these strategies are also easy and inexpensive, or even totally free, to implement. These are some of the other options to reduce your blue light exposure and help mitigate the damage caused by excessive nighttime blue light exposure.
- Avoid all digital screens in the two or three hours before bedtime.
- Install an app such as f.lux or https://iristech.co/ or activate ‘night mode’ on all your electronic devices to reduce blue light levels, especially after dark.
- Use red bulbs for your night lights to reduce eye strain. Soft red lights are much easier on the eyes than white bulbs, which contain high levels of blue light, especially at night.
- During the daytime, spend time outdoors in the sun or in well-lit areas to help normalize your body’s circadian rhythms.
- Opt for soft white or yellow light bulbs in your home rather than bright white.
- When working in front of a screen, take frequent breaks to relieve your eyes and prevent digital eye strain.
- Blink frequently when using a screen, as this can help keep your eyes moist and prevent digital eye strain.
- If you’re concerned about your vision, try supplementing with lutein and zeaxanthin or eating a diet rich in green, red, and orange vegetables. These antioxidants may help decrease your risk of macular degeneration and protect your eyes from light damage. (14)
Blue light exposure may seem like a minor issue, especially compared to other environmental factors that are linked to devastating chronic health conditions. However, I implore you to recognize how sleep affects your overall health and how seriously blue light can interfere with your sleep.
In my opinion, glasses designed to block blue light are an easy and non-intrusive way to minimize your health risks and help maximize the quality of your sleep. If you’re interested in learning more about how your environment can affect or is affecting your health, then please don’t hesitate to read the other posts on the Hoffman Centre blog or contact my office to set up an appointment.
- Renard G, Leid J. Les dangers de la lumière bleue : la vérité ! [The dangers of blue light: True story!]. J Fr Ophtalmol. 2016 May;39(5):483-8. French. doi: 10.1016/j.jfo.2016.02.003. Epub 2016 Mar 31.
- Holzman DC. What’s in a color? The unique human health effect of blue light. Environ Health Perspect. 2010;118(1):A22-A27. doi:10.1289/ehp.118-a22
- Rucker F, Britton S, Spatcher M, Hanowsky S. Blue Light Protects Against Temporal Frequency Sensitive Refractive Changes. Invest Ophthalmol Vis Sci. 2015 Sep;56(10):6121-31. doi: 10.1167/iovs.15-17238.
- Torii H, Kurihara T, Seko Y, Negishi K, Ohnuma K, Inaba T, Kawashima M, Jiang X, Kondo S, Miyauchi M, Miwa Y, Katada Y, Mori K, Kato K, Tsubota K, Goto H, Oda M, Hatori M, Tsubota K. Violet Light Exposure Can Be a Preventive Strategy Against Myopia Progression. EBioMedicine. 2017 Feb;15:210-219. doi: 10.1016/j.ebiom.2016.12.007. Epub 2016 Dec 16.
- Coles-Brennan C, Sulley A, Young G. Management of digital eye strain. Clin Exp Optom. 2019 Jan;102(1):18-29. doi: 10.1111/cxo.12798. Epub 2018 May 23. PMID: 29797453.
- Sheppard AL, Wolffsohn JS. Digital eye strain: prevalence, measurement and amelioration. BMJ Open Ophthalmol. 2018 Apr 16;3(1):e000146. doi: 10.1136/bmjophth-2018-000146.
- Zhao ZC, Zhou Y, Tan G, Li J. Research progress about the effect and prevention of blue light on eyes. Int J Ophthalmol. 2018 Dec 18;11(12):1999-2003. doi: 10.18240/ijo.2018.12.20.
- Modenese A, Gobba F. Macular degeneration and occupational risk factors: a systematic review. Int Arch Occup Environ Health. 2019 Jan;92(1):1-11. doi: 10.1007/s00420-018-1355-y. Epub 2018 Sep 6.
- Alaimo A, Liñares GG, Bujjamer JM, et al. Toxicity of blue led light and A2E is associated to mitochondrial dynamics impairment in ARPE-19 cells: implications for age-related macular degeneration. Arch Toxicol. 2019;93(5):1401-1415. doi:10.1007/s00204-019-02409-6
- Marie M, Gondouin P, Pagan D, et al. Blue-violet light decreases VEGFa production in an in vitro model of AMD. PLoS One. 2019;14(10):e0223839. Published 2019 Oct 23. doi:10.1371/journal.pone.0223839
- West KE, Jablonski MR, Warfield B, et al. Blue light from light-emitting diodes elicits a dose-dependent suppression of melatonin in humans. J Appl Physiol (1985). 2011;110(3):619-626. doi:10.1152/japplphysiol.01413.2009
- Bonmati-Carrion MA, Arguelles-Prieto R, Martinez-Madrid MJ, Reiter R, Hardeland R, Rol MA, Madrid JA. Protecting the melatonin rhythm through circadian healthy light exposure. Int J Mol Sci. 2014 Dec 17;15(12):23448-500. doi: 10.3390/ijms151223448. PMID: 25526564; PMCID: PMC4284776.
- Shechter A, Kim EW, St-Onge MP, Westwood AJ. Blocking nocturnal blue light for insomnia: A randomized controlled trial. J Psychiatr Res. 2018;96:196-202. doi:10.1016/j.jpsychires.2017.10.015
- Jia YP, Sun L, Yu HS, et al. The Pharmacological Effects of Lutein and Zeaxanthin on Visual Disorders and Cognition Diseases. Molecules. 2017;22(4):610. Published 2017 Apr 20. doi:10.3390/molecules22040610
- National Institute of General Medical Sciences. Circadian Rhythms Fact Sheet. https://www.nigms.nih.gov/education/fact-sheets/Documents/fact-sheet-circadian-rhythms.pdf
- Sleep Disorder Resource. Circadian Rhythm Sleep Disorder. http://www.sleepdisordersresource.com/circadian-rhythm-sleep/cricadian-rhythm-sleep/circadian-rhythm-sleep-disorder/
Dr. Bruce Hoffman, MSc, MBChB, FAARM, IFMCP is a Calgary-based Integrative and Functional medicine practitioner. He is the medical director at the Hoffman Centre for Integrative Medicine and The Brain Centre of Alberta specializing in complex medical conditions. He was born in South Africa and obtained his medical degree from the University of Cape Town. He is a certified Functional Medicine Practitioner (IFM), is board certified with a fellowship in anti-aging (hormones) and regenerative medicine (A4M), a certified Shoemaker Mold Treatment Protocol Practitioner (CIRS) and ILADS trained in the treatment of Lyme disease and co-infections. He is the co-author of a recent paper published by Dr. Afrin’s group: Diagnosis of mast cell activation syndrome: a global “consensus-2”. Read more about Dr. Bruce Hoffman.