Optometry Tidbit
Jessica Hu
Physiological Sciences Major
Class of 2018
Blue Light
With the increasing use of digital screens in our everyday lives, it is useful to examine the consequences of excess exposure to blue light. Studies have found evidence showing that long-term blue light adversely affects our eyes and our overall health. While there are still some beneficial roles blue light play in our health, it is important to protect our eyes to maintain long-term health.
Blue light refers to the part of the visible light spectrum generally described as falling between 400 and 460 nm in wavelength. Even though white light is produced by a combination of all the colors of this spectrum, blue light is particularly damaging because it penetrates most deeply in our eyes, where it can affect the retina. (Dunbar)
Our eye and overall health can be benefited from some levels of exposure to blue light. Sunlight may be comprised of about 25-30% blue light during the day, at similar levels to the proportion found in LED lights. (Dunbar) Of course, a much shorter duration of exposure of direct sunlight can have more drastic effects on our eyes. Research has suggested that the blue-turquoise light range, specifically from 465 nm to 496 nm, plays beneficial roles on the circadian clock system, which functions to regulate our sleep/wake cycles.
Blue light found in both digital devices and room lighting can cause more adverse effects by increasing exposure. Chang et al. found that blue light emitted from modern eReaders causes delays in circadian clock cycles, a decline in REM sleep amount, and an increased alertness at the time of use, which would lead to a delayed sleep time, in people who read with these devices before bed. Some also attribute digital eye strain symptoms to excessive use of digital screens. This might be caused by a tendency to stare at screens for extended periods and by the lower rate of blinking during screen use, though the same detrimental effects of blue light may also contribute to eye fatigue. (Eyestrain) LED light bulbs have also become more prevalent in use due to their energy-saving properties. Blue light was found in greater amounts in LED lights than other commercially available lights, which researchers also categorized as having higher risk on eye health in longer exposure times. (Behar-Cohen et al.)
While this data may seem intimidating, these effects are discussed as possibilities of long-term excess blue light exposure. As a result, simple solutions in our daily use of digital screens can help to reduce blue light exposure and help to protect our vision in the long run. Some suggestions include making sure the screen is slightly below eye level and 20-26 inches away from your eyes, and activating blue light filter applications or functions on devices. Using computer glasses with photochromic lenses that filter out blue light, and using lenses with anti-reflective coating or tints may also help to alleviate eye strain while using digital devices. (Heiting, Blue Light and Your Eyes) Thus with the proper care, we can reduce our risks for vision complication with accumulated blue light exposure.
Works Cited
1. Behar-Cohen, F., Martinsons, C., Vienot, F., Barlier-Salsi, A., Cesarini, JP., Enouf, O., Garcia, M., Picaud, S., Attia., D. 2011. Light-emitting diodes (LED) for domestic lighting: any risks for the eye? Progress in Retinal and Eye Research. 30(4):239-257.
2. Blue Light and Your Eyes. Retrieved December 06, 2017, from
https://www.preventblindness.org/blue-light-and-your-eyes
3. Dunbar, M., Melton, R., The lowdown on blue light: good vs. bad, and its connection to AMD. Review of Optometry. 2014.
4. Chang, AM., Aeschbach, D., Duffy, JF., Czeisler, CA. Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Proceedings of the National Academy of Sciences of the United States of America. 112(4):1232-1237.
5. Eyestrain. (2015, August 13). Retrieved December 06, 2017, from https://www.mayoclinic.org/diseases-conditions/eyestrain/symptoms-causes/syc-20372397
6. Heiting, G., OD. Computer Glasses That Help Relieve Computer Eye Strain. Retrieved December 06, 2017, from http://www.allaboutvision.com/cvs/computer_glasses.htm