The Effectiveness of Blue Light Glasses
Hours on the computer can disrupt one’s circadian rhythms as well as create problematic eye fatigue. Why might this be the case? This is due to high levels of short-wavelength light being emitted from the computer screen. Thanks to the pandemic, most days consist of hours on Zoom and therefore excessive exposure to blue short-wavelength light (blue light). Many people wonder, how could light waves from the computer do so much damage? Blue light has the most energy of all light in the visible electromagnetic spectrum (Lin, 442). Compared to other wavelengths of light, this light can be greatly damaging to the human body particularly to the eyes.
Light toxicity in the retina of the eye occurs when excess light causes “photochemical, photomechanical and photothermal damage.” (Lin 442). Not only can this damage create acute issues in the vision like eye strain and fatigue, but chronic problems as well. In addition, blue light affects the production of hormones essential for regulating the circadian rhythm. Circadian rhythms are internally driven cycles that rise and fall during a 24 hour period and assist in providing bodily cues for when one should wake up and go to sleep (CDC). Harvard Health attributes blue light’s effects on circadian dysregulation to reduction of melatonin: “While any kind of light can suppress the secretion of melatonin, blue light at night does so more powerfully. Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to green light of comparable brightness. The blue light suppresses melatonin for about twice as long as green light and shifted circadian rhythms by twice as much” (Harvard Health).
This has created a large market for blue light blocking glasses. Retail stores across the United States have added blue light glasses to their inventory, selling them as they would sunglasses or other accessories. Celebrities and influences have also been raving about their own positive experiences after buying blue light glasses. The question remains whether blue light blocking glasses are actually effective at reducing eye fatigue and combating dysregulation of circadian rhythm. A study conducted by the Department of Ophthalmology and Visual Sciences at Washington University School of Medicine aimed to answer half of this question. The study used Critical Flicker Fusion Frequency (CFF) as a measurement of eye strain. 36 subjects were evaluated before and after a 2-hour computer task where the participants were randomly given either control, low, or high blocking lenses. Results found that “blue-blocking glasses reduce eye fatigue associated with excessive blue light exposure” with high blocking lenses showing the greatest improvement in eye strain (Lin, 444). Following this study, many other researchers using similar conditions found the same results.
A study from The Journal of Biological and Medical Rhythm Research evaluated whether patients with delayed sleep phase disorder (DSPD) or the inability to fall asleep and wake up at conventional times were affected by wearing blue light glasses before bed. To ascertain the outcome of the intervention, the researchers “measured dim light melatonin onset (DLMO) and actigraphic sleep data at baseline and after the treatment” (Eskai, 1037). The results showed an advanced sleep onset time meaning the participants went to bed earlier than usual by over 2 hours. We can infer from this data that circadian rhythms were positively regulated in the DSPD patients who wore blue light glasses before bed.
Overall, most studies prove the purported benefits of blue light glasses are credible. Not only can they improve sleep quality, but they also assist in the reduction of eye fatigue and chronic issues associated with long term eye strain. As the pandemic drudges on and long hours on the computer become inevitable, it may not be a bad idea to look into blue light glasses and the long term benefits that come with them.
References:
CDC. Circadian Rhythms and Circadian Clock. 1 Apr. 2020, www.cdc.gov/niosh/emres/longhourstraining/clock.html.
Esaki, Yuichi, 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.” Chronobiology International, vol. 33, no. 8, 2016, pp. 1037–1044., doi:10.1080/07420528.2016.1194289.
Lin, Jonathan B., et al. “Short-Wavelength Light-Blocking Eye Glasses Attenuate Symptoms of Eye Fatigue.” Investigative Ophthalmology & Visual Science, vol. 58, no. 1, 2017, p. 442., doi:10.1167/iovs.16-20663.
Harvard Health. Blue Light Has a Dark Side. www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side.
