Blue-light Blocking Glasses

ByIsabella

Blue-light blocking glasses have become a popular addition to the roster of wellness products – available at the opticians, in Boots or on amazon prime. The idea is that the blue light emitted by screens strains your eyes, damages your retinas and wrecks your sleep, so the glasses filter it out and allow us to scroll right up until we go to sleep without the unwanted effects. 

Where did the worry come from?

The biology behind the effects of blue light is genuine – the retina (the back of the eyeball) contains a small group of cells (called intrinsically photosensitive retinal ganglion cells or ipRGCs) that aren’t for vision, but for telling your brain what time of day it is. They contain a pigment called melanopsin, which is most sensitive to short-wavelength light, which is what we see as blue. When these cells fire, they signal to the brain to stop the release of melatonin, the hormone associated with sleep. This is why using screens that emit a lot of blue light in the evening can delay sleep, shift your circadian rhythm, and reduce next-morning alertness. 

In true wellness culture fashion, rather than just adjusting our behaviour, the production of tinted glasses claiming to filter out the harmful blue-light began. However, the efficacy of these lenses doesn’t always meet the bold claims advertised…below, I’ve outlined what the evidence actually says about some of these claims.

A 2023 Cochrane review (the closest thing medicine has to a gold standard!) looked at results from 17 randomised controlled trials involving 619 people and concluded that blue-light filtering lenses may offer no short-term advantage over ordinary clear lenses for reducing visual fatigue during computer work. The trials were small and short, and the review’s authors were careful to flag that limitation, but the direction of the finding was consistent. An earlier systematic review in 2017 had also reached the same conclusion, just from a smaller evidence base. 
Importantly in 2021, researchers at the University of Melbourne ran a trial in which participants received either blue-blocking or clear placebo lenses, but were all told they had the blue-light blockers. Everyone then did a two-hour computer task. The results showed the lenses had no significant effect on eye strain symptoms, nor on critical flicker-fusion frequency (an objective measure of visual fatigue). 
The truth is sore eyes after a day of looking at your computer are caused by your eye muscles getting tired and your blink rate dropping substantially during concentrated work (which makes them dry and ‘gritty’). This means tinted glasses won’t be able to stop that feeling… 

A 2025 systematic review and meta-analysis found the blue-light glasses did improve sleep onset latency by about five minutes and total sleep time by roughly nine minutes, but these findings were statistically insignificant because of the size and quality of the experiments. Sleep efficiency and time awake after falling asleep also showed nothing meaningful. Heterogeneity across the studies was zero, meaning the trial were consistent with one another and all pointed to the same small, imprecise, non-significant result. 

However, before we can conclude that “they don’t work”, there are several things to consider. Firstly, the lenses of these glasses vary enormously – a 2025 paper proposed a standardised metric (melanopic daylight filtering density) to measure how much circadian-relevant light a lens actually removes, and found massive variability across commercially available products all being sold under the same label of “blue-light blocking”, but many filter too little short-wavelength light to plausibly change melanopsin signalling at all.  

This same study noted that none of the included trials had measured the intensity, spectrum or timing of the melanopic light exposure reaching the eyes of participants. Without this there’s no way to really tell if filtering blue light just doesn’t really affect sleep, or whether they were just not strong enough to remove a large amount of the blue light. 

Interestingly, evidence also suggests the impact of blue-light blocking lenses is more prominent in people with disorders that negatively affect their sleep (like bipolar mania, depression with sleep onset insomnia, and chronic insomnia) than in healthy sleepers. This makes sense since someone already sleeping relatively well has much less room to improve than those with severe circadian misalignment. However, no clinical guidelines currently endorse blue-blocking glasses as a standard treatment for insomnia or sleep disorders, so if you’re struggling with this, I’d always recommend seeing your GP.  

So, it’s not that the glasses don’t work, but any effect is small, very easily lost in weak lenses and most likely to be noticed by those with very disturbed sleep. 

The fear of blue light damaging your eyes likely stems from experiments that showed intense blue light can harm retinal cells. However, these studies used light intensities and exposure durations far beyond anything your phone could produce (and they were done on rodent retinas, which are more sensitive to injury than ours).  
In 2016, researchers at Public Health England measured the blue light output of a range of lightbulbs, computers, laptops, tablets and phones and found none of the sources came close to the limits at standard daily usage levels. For context, they also measured the blue light exposure you’d get from simply looking at a blue sky, and this was higher than all the devices.

Are there any risks?

Not really, which is partly why the trend is able to keep going despite the lack of supporting evidence…it’s harmless to try! The Cochrane review found adverse effects were temporary and generally mild (like headache and discomfort wearing the glasses), and similar complaints appeared in the clear-lens groups too, suggesting they related to wearing glasses rather than the special lenses.

HOWEVER…

Wearing these glasses all day wouldn’t be advised. As I’ve mentioned, blue light plays an important role in our circadian rhythm – we might not want it to suppress melatonin and keep us awake at night, but in the daytime, it is vital in allowing us to feel energised and alert. In honesty, most readily available blue-light glasses probably won’t be strong enough to have any serious effects, but if you chance upon some strong lenses, ensure to only wear them in the evening! 

REMEMBER…

Your devices can already offer – ‘night mode’ and warmer colour profiles shift a display’s spectrum away from short wavelengths, and turning the brightness down reduces the total light reaching your eyes. As is often the case, the interventions with the best supporting evidence are the least marketable (and fun) of all: dimming the lights in the evening, keeping consistent sleep and wake times, and getting bright light exposure during the day. 

Below are the DOI codes for the studies I used to collect the information in this post. Just copy and paste these into your search engine to read the full journal articles:

  1. 10.1002/14651858.CD013244.pub2 
  1. 10.1016/j.ajo.2021.02.010 
  1. 10.1111/opo.12406 
  1. 10.3389/fneur.2025.1699303 
  1. 10.1093/sleepadvances/zpaa002 
  1. 10.1167/tvst.14.7.25 
  1. 10.1038/eye.2015.261 
  1. 10.1073/pnas.1418490112 
  1. 10.1111/j.1475-1313.2011.00834.x 
  1.  10.1016/j.sleh.2021.02.004 
  1.  10.1111/jsr.12984 
  1.  10.1080/07420528.2017.1316737 
  1.  10.1016/j.biopha.2020.110577 

14. 10.3389/fphys.2022.943108 

Leave a Reply

Your email address will not be published. Required fields are marked *