The Truth Behind Blue-Light Glasses
Written by Allyson Monsada
Edited by Sam Levya
April 5, 2024
Edited by Sam Levya
April 5, 2024
Health and Wellness
You’ve probably heard of blue–light glasses from your local optometrist or just in your local pharmacy. With digital devices now a near necessity everywhere, concerns have been raised about the adverse effects our screens could have on our eyes. Blue light glasses became the novel solution for this issue, but what exactly do they do and do they work? A Chrocane review sought to investigate this by observing how blue light-filtering glasses impacted visual performance, sleep, and macular health in adults (Downie et al. 2019). Cochrane reviews are well-known within the scientific community for maintaining the highest standard in evidence-based healthcare due to their strict methodical approaches.
First, what is blue light and how is it harmful? Sunlight reaches Earth as solar or electromagnetic radiation, some well-known examples being ultraviolet (UV) radiation and visible light. The former is well known for its harmful effects on our eyes or skin. The latter is what the human eye can see, for example, traditional incandescent light bulbs or LEDs. UV radiation falls between the 200-400 nm range in the electromagnetic spectrum and visible light, between 400-760 nm. Blue light is a part of the visible spectrum and lies between 400-500 nm. Blue light lies quite close to the UV range, and digital screens tend to be the largest source of blue light emitted to our eyes, outside the sun (Downie et al. 2019).
Previous studies on the effects of blue light have investigated whether there is a true correlation between blue light and visual strain. Blue light is commonly attributed to asthenopic symptoms like eye fatigue, sore eyes, headaches, or, blurred vision. There is substantial evidence to support that the use of electronics before going to sleep affects sleep quality too. Our sleep-wake cycle is regulated by the secretion of the hormone melatonin, with low levels of melatonin corresponding with daytime alertness (Downie et al. 2019). Blue light exposure has been proven to inhibit melatonin secretion so it follows that nighttime blue light exposure could disrupt sleep.
The Crochane review utilized randomized controlled trials (RCTs). The RCTs were organized into two groups of adults, one with blue-light filtering glasses and the other with non-blue light filtering glasses to compare the effects. The results of the tests would be categorized into either primary outcomes such as changes in visual fatigue or CFF and secondary outcomes like changes in other ocular functions and sleep quality. The review takes into account any possible positive and negative changes that could occur due to blue light glasses to reach a well-rounded conclusion (Downie et al. 2019).
The results were compiled in 2023 where it was concluded that blue light glasses had little to no effect on visual strain due to blue light exposure when compared to non-blue light filtering glasses (Downie et al. 2019). While blue light glasses aren’t harmful and there seems to be no harm in using them, it is important to note that their protective quality against visual strain has not been proven. Research is still ongoing on other hopeful protective measures against blue light or visual strain. In the meantime it is important to be mindful of prolonged exposure to screens for the benefit of your eyes!
Reference:
Downie LE, Keller PR, Busija L, Lawrenson JG, Hull CC. Blue‐light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database of Systematic Reviews. 2019. Issue 1. Art. No.: CD013244. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013244/full.
First, what is blue light and how is it harmful? Sunlight reaches Earth as solar or electromagnetic radiation, some well-known examples being ultraviolet (UV) radiation and visible light. The former is well known for its harmful effects on our eyes or skin. The latter is what the human eye can see, for example, traditional incandescent light bulbs or LEDs. UV radiation falls between the 200-400 nm range in the electromagnetic spectrum and visible light, between 400-760 nm. Blue light is a part of the visible spectrum and lies between 400-500 nm. Blue light lies quite close to the UV range, and digital screens tend to be the largest source of blue light emitted to our eyes, outside the sun (Downie et al. 2019).
Previous studies on the effects of blue light have investigated whether there is a true correlation between blue light and visual strain. Blue light is commonly attributed to asthenopic symptoms like eye fatigue, sore eyes, headaches, or, blurred vision. There is substantial evidence to support that the use of electronics before going to sleep affects sleep quality too. Our sleep-wake cycle is regulated by the secretion of the hormone melatonin, with low levels of melatonin corresponding with daytime alertness (Downie et al. 2019). Blue light exposure has been proven to inhibit melatonin secretion so it follows that nighttime blue light exposure could disrupt sleep.
The Crochane review utilized randomized controlled trials (RCTs). The RCTs were organized into two groups of adults, one with blue-light filtering glasses and the other with non-blue light filtering glasses to compare the effects. The results of the tests would be categorized into either primary outcomes such as changes in visual fatigue or CFF and secondary outcomes like changes in other ocular functions and sleep quality. The review takes into account any possible positive and negative changes that could occur due to blue light glasses to reach a well-rounded conclusion (Downie et al. 2019).
The results were compiled in 2023 where it was concluded that blue light glasses had little to no effect on visual strain due to blue light exposure when compared to non-blue light filtering glasses (Downie et al. 2019). While blue light glasses aren’t harmful and there seems to be no harm in using them, it is important to note that their protective quality against visual strain has not been proven. Research is still ongoing on other hopeful protective measures against blue light or visual strain. In the meantime it is important to be mindful of prolonged exposure to screens for the benefit of your eyes!
Reference:
Downie LE, Keller PR, Busija L, Lawrenson JG, Hull CC. Blue‐light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database of Systematic Reviews. 2019. Issue 1. Art. No.: CD013244. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013244/full.
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