Visible blue light

While there is evidence to suggest that digital devices can increase eye-strain for those that use them for extended periods of time and can impact on sleep patterns, there is currently insufficient evidence to say that blue light from digital devices contributes in any significant way to the development of eye conditions such as age-related macular degeneration (AMD).

Coatings that filter blue light may improve visual comfort for some patients, or help mitigate the impact of blue light on sleep, but there is a lack of sufficient evidence in humans to support claims that they prevent eye disease. Existing studies offer no statistically significant evidence of clinical improvement. The AOP does not support any new procedures or products for which there is either contrary evidence or no supporting evidence. It should also be noted that blue light filtering coatings typically do not block all blue light but instead filter out between 10-35% of the blue light in the violet-blue range (380-500 nm).

This position statement reviews the evidence for the use of coatings to filter blue light. It also provides advice related to patient concerns about screen use and blue light from digital devices.

What the evidence tells us

There is no appropriate evidence in humans that blue light from digital devices is connected with eye disease. A 2016 paper reviewing the evidence concluded that short- and medium-term exposure to low-levels of blue light should not have an impact on eye health but suggested further research was needed.¹

A 2017 systematic review concluded that there was “a lack of high quality evidence to support using BB [Blue Blocking] spectacle lenses for the general population to improve visual performance, sleep quality, or alleviate eye fatigue”.²

While there is some evidence that the violet-blue light contributes to advanced ageing of the retina (ISO TR-20772), the amount of violet-blue light emitted from most digital devices is less than 5% of the intensity the eye would receive when outdoors on a sunny day. It is thought that any photochemical damage from violet-blue light is likely to be based on cumulative exposure and therefore the low intensities emitted from digital devices mean that not they are unlikely to  significantly factor.³

And a systematic review carried out in 2021 concluded that there ‘is a lack of consistent evidence for a larger-scale introduction of BB (blue blocking) lenses in routine clinical practice.’ It also suggested that the disadvantages, as well as benefits, of BB lenses needed to be weighed up.⁴

A 2023 Cochrane review⁵ assessed the available evidence of the effectiveness of blue light filtering spectacles for improving visual performance, providing macular protection and improving sleep quality in adults. Specific measures included “change in visual fatigue score and critical flicker‐fusion frequency (CFF), as continuous outcomes, between baseline and one month of follow‐up, best‐corrected visual acuity (BCVA), contrast sensitivity, discomfort glare, proportion of eyes with a pathological macular finding, colour discrimination, proportion of participants with reduced daytime alertness, serum melatonin levels, subjective sleep quality, and patient satisfaction with their visual performance”. No positive outcomes were clear on any of these measures in the studies they assessed.

In its 2015 ruling on claims about coatings to filter visible blue light, the Advertising Standards Authority (ASA) concluded that the evidence could not substantiate the claims made for visible blue light, saying: “only full trials conducted on humans were sufficient, potentially, to support the claims. We assessed the relevant study submitted by Boots and noted that although it included a large number of participants who were followed up over several years, it was one single epidemiological study which only suggested that sunlight and not blue-violet light in particular, might be a risk factor for the early onset of age-related macular degeneration (AMD).”⁶

A two year study compared the effect of UV blocking only with UV blocking + blue filtering intraocular lenses (IOLs) and found no difference in visual acuity, contrast sensitivity, colour vision or prevalence of retinal diseases.⁷ 

However, none of these studies look at the long-term effect of visible blue light exposure and eye disease. 

There have been studies of the effects of visible blue light irradiation on the retinas of rats⁹ and rhesus monkeys.¹⁰ The length and intensity of exposure to visible blue light in these studies far exceeded that of natural daylight or screen use. Therefore, no conclusion can be drawn as to the likely effect on humans of normal exposure to visible blue light. Due to obvious ethical issues, no studies have been carried out on humans.

From reviewing available evidence, the AOP concludes that there is insufficient evidence to support the contention that visible blue light exposure from digital devices leads to ocular pathology and damage to eye health.

Screen use and sleep patterns

There is some evidence that use of digital devices which emit visible blue light in the evening, may affect the circadian cycle, and lead to delayed sleep.¹¹ This may be because visible blue light is linked to suppression of the hormone melatonin which makes us feel sleepy. It has been suggested that digital devices should vary the light spectrum (wavelengths) they emit across the day to fit our sleep patterns. Other changes that can be made include, altering the screen colour temperature, avoiding the use of digital devices prior to sleeping and utilising technologies such as night mode. There are a range of other factors also linked to disrupted sleep patterns.

Excessive time spent in using near vision for example reading and digital device use, is sometimes associated with eye-strain and headaches, the College of Optometrists conducted a literature review led by Professors Lawrenson and Hull and came to the conclusion that the best scientific evidence does not support that blue light blocking spectacles improved visual performance, or alleviated the symptoms of eye fatigue or visual discomfort.

AOP advice to members

Patients often express concerns about screen use to optometrists, as revealed by the following results from our 2017 Voice of Optometry survey carried out with 1131 UK optometrists:

• More than nine in 10 UK optometrists had seen patients in the past month who reported problems as a result of screen use, such as dry eyes, headaches or eye strain
  
  
• Almost as many had seen patients who were worried that screen use was detrimental to their, or their children’s, eye health

We believe that more needs to be done to educate the public about screen use. Useful advice could include:

• There is no clear evidence that visible blue light causes eye disease in humans
  
  
• Using screens close to bedtime may contribute to poorer sleep, which can make a person less effective during the day
  
  
• Turning off any digital devices up to an hour before sleeping can help aid sleep
  
  
• Using night settings, if your device has them, can aid sleep by decreasing the amount of visible blue light emitted by the screen during night time hours
  
  
• To avoid eye strain people should adhere to the 20/20/20 rule, every 20 minutes, look away from your screen at something at least 20 feet away for 20 seconds
  
  
• Have a sight test every two years, or more often if your optometrist recommends it

References

1. Tosini G, Ferguson I, Tsubota K (2016) Effects of blue light on the circadian system and eye physiology. Molecular vision and genetics in vision research, 22(61)
2. Lawrenson JG, Hull CC & Downie LE (2017) The effect of blue-light blocking spectacle lenses on visual performance, macular health and the sleep-wake cycle: a systematic review of the literature. Ophthalmic Physiological Optics ; 37: 644–654. https://doi.org/10.1111/opo.12406
3. ISO, I. O. F. S. 2018. Ophthalmic optics — Spectacle lenses — Short wavelength visible solar radiation and the eye: Technical Report TR-20772. Geneva: ISO copyright office
4. Singh S, Keller PR, Busija L, McMillan P, Makrai E, Lawrenson JG, Hull CC, Downie LE. Blue‐light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database of Systematic Reviews 2023, Issue 8. Art. No.: CD013244. DOI: 10.1002/14651858.CD013244.pub2. Accessed 21 August 2023
5. Vagge, A., Ferro Desideri, L., Del Noce, C., Di Mola, I., Sindaco, D., & Traverso, C. E. (2021, October). Blue light filtering ophthalmic lenses: A systematic review. In Seminars in Ophthalmology (Vol. 36, No. 7, pp. 541-548). Taylor & Francis
6. Advertising Standard Authority (2015) ASA Ruling on Boots Professional Services Ltd t/a Boots Opticians Ltd published online 28 October 2015
7. Lavric A, Pompe MT (2014) Do blue-light filtering intraocular lenses affect visual function? Optometry and Vision Science, 91(11), 1348-54
8. Li X, Kelly D, Nolan J M, Dennison JL, Beatty S (2016) The evidence informing the surgeon’s selection of intraocular lens on the basis of light transmittance properties. Eye, published online 9 December 2016
9. Seko Y, Pang J, Tokoro T, Ichinose S, Mochizuki M (2001) Blue light-induced apoptosis in cultured retinal pigment epithelium cells of the rat. Graefe's archive for clinical and experimental ophthalmology
10. Ham WT, Ruffolo JJ, Mueller HA & Guerry D (1980) The nature of retinal radiation damage: dependence on wavelength, power level and exposure time. Vision Research, 20(12)
11. Cajochen C, et al. (2011) Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. Journal of Applied Physiology, 110(5), 1432-1438
    
     

Read the rest of the AOP position statements.