Do We Need Blue-Light Filtering Lenses?

By Dr Suklengmung Buragohain

Date: 17/05/2022

We have come across many advertisements for blue light filtering lenses for spectacles on television, in spectacle shops or outside eye clinics. On the internet as well you can observe that as soon as you insert the words “Blue light filtering lenses” into the google search engine an extensive list drops down in front of you telling you why you should be getting those lenses and why blue light is harmful to you. If big spectacle companies claim such a thing then that must be true right? Or is it? Let us review what science tells us. 

Background

The wavelength of light that humans can perceive ranges from 380 to 700 nanometers (nm) and blue light falls within this range with a wavelength of 450nm. It has been observed that digital devices such as smartphones and computers with backlit LED displays seem to emit a higher level of short-wavelength visible light (such as blue light) than traditional sources of light.1,2 

Is Blue Light Harmful For The Eye?

With the increasing use of digital devices, an extensive number of people have reported having complaints such as sore eyes, eye fatigue, headaches, blurred vision, and dry eye.3 Such symptoms have been classified collectively as “Computer Vision Syndrome” or CVS in scientific literature. Having said this, it is however not clear whether blue light plays any role in developing CVS as the nature of CVS is multifactorial (binocular vision disorders, uncorrected refractive error or presbyopia, and tear film dysfunction). 4 Two randomized control trials that compared blue filtering lenses and normal lenses found that blue filtering lenses do not provide any relief from digital eye strain. 5,6 In simple terms, the usage of digital devices can cause symptoms of CVS but there is no scientific evidence that those symptoms are due to blue light emitting from the screens. 

There are also reports of deleterious effects of blue light on the sleep cycle. There have been studies conducted that report that there is an association between evening use of electronic devices and adverse sleep quality, altered circadian timing and reduced daytime alertness.7,8 This is of concern as there is evidence that suggests that disruptions to biological cycles and the circadian rhythm can have potentially adverse effects on a diverse range of health parameters. 9 Thus, sleep and related conditions can be affected by blue light. 

Many advertising agencies claim that blue light filtering lenses help in preventing damage to the retina (which is responsible for vision) of the eye. A few animal studies show that blue light can cause retinal damage, but there is no such evidence of something similar happening in humans yet. 10,11 So with the scientific evidence that we have at present, we cannot claim that blue light is injurious to the human retina. 

Why Is This Topic Important?

Many companies have been pitching the idea that blue light causes substantial damage to the retina along with symptoms of CVS and have been selling blue light filtering lenses as a means of protecting the eyes from it. This claim however doesn’t seem to have any scientific backing (at least at present), and it is important that an average customer knows this fact. In 2015, the UK Advertising Standards Authority (ASA) found that a retailer was putting misleading claims that blue light causes retinal damage and was subsequently fined. 12 

How To Reduce Eye Strain Due to Use Of Digital Screens?

There are a few simple habits that we can adopt in our daily work while working with digital screens to reduce eye strain. These methods are recommended by the American Association of Ophthalmology (AAO) and are given below:

• Keep your screen at 25 inches or at an arm's length 

• Look slightly down towards the screen.

• Follow the 20-20-20 rule - look away from the screen to an object at least 20 feet away for 20 seconds every 20 minutes (gives the eyes a break)

• If the eyes feel dry then use artificial tears.

• Adjust the lighting in the room and the contrast levels of the screen

• Use a matte screen filter if needed.

• If you have been prescribed spectacles with powered lenses then use them while looking at the screen. 

Conclusion

There is at present no clinical evidence that blue light emitted from digital screens is harmful to your eyes. There is also no evidence that blue light filtering lenses can prevent symptoms of eye strain due to screen time. 

References

1. O'Hagan JB, Khazova M, Price LL. Low‐energy light bulbs, computers, tablets and the blue light hazard. Eye 2016;30(2):230‐3.

2. Cziesler CA. Perspective: casting light on sleep deficiency. Nature 2013;497(7450):S13

3. Rosenfield M. Computer vision syndrome: a review of ocular causes and potential treatments. Ophthalmic and Physiological Optics 2011;31(5):502‐15..  

4. American Optometric Association. Guide to the Clinical Aspect of Computer Vision Syndrome. St Louis: American Optometric Association, 1995.

5. Jesús Vera,Beatriz Redondo,Alba Ortega-Sanchez,Alejandro Molina-Molina,Rubén Molina,Mark Rosenfield &Raimundo Jiménez. Blue-blocking filters do not alleviate signs and symptoms of digital eye strain. Clinical and Experimental Optometry. Jan 2020

6. Sumeer Singh, Laura E. Downie, Andrew J. Anderson. Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial. American Journal of Ophthalmology. Volume 226. 2021:243-251   

7. 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 2015;112(4):1232–7

8. Gamble AL, D'Rozario AL, Bartlett DJ, Williams S, Bin YS, Grunstein RR, et al. Adolescent sleep patterns and night‐time technology use: results of the Australian Broadcasting Corporation's Big Sleep Survey. PLoS One 2014;19(11):e111700.

9. Hatori M, Gronfier C, Gelder RN, Bernstein PS, Carreras J, Panda S, et al. Global rise of potential health hazards caused by blue light‐induced circadian disruption in modern aging societies. NPJ Aging and Mechanisms of Disease 2017;16(3):9.

10. Ham WT, Mueller HA, Ruffolo JJ Jr, Guerry D, Guerry RK. Action spectrum for retinal injury from near‐ultraviolet radiation in the aphakic monkey. American Journal of Ophthalmology 1982;93(3):299‐306.

11. Noell WK, Walker VS, Kang BS, Berman S. Retinal damage by light in rats. Investigative Ophthalmology 1966;5(5):450‐73. 

12. United Kingdom Advertising Standards Authority (ASA). ASA ruling on Boots Professional Services Ltd t/a Boots Opticians Ltd. www.asa.org.uk/rulings/boots‐professional‐services‐ltd‐a15‐293200.html