Despite my wife calling me “Bono” (which hurts, I’ll be honest), I’ve been wearing a pair of Swanwick blue light blocking glasses every evening for several years. They may look a bit daft, with their orange lenses, but I’m convinced they’ve improved my sleep.

I could be wrong, but there is some evidence to suggest I might be right.

Given the growing popularity of blue light blocking glasses, and the way they’re marketed, you’d think there was mountains of supporting evidence from rigorous studies. There isn’t, unfortunately.

But we do have 12 small trials (although four of them were not controlled) which, together, suggest that wearing blue light blocking glasses before bed may moderately improve sleep.

In the summer of 2020, a team of researchers in New York published a systematic review and meta-analysis of these 12 trials. They found that wearing blue light blocking glasses before bed:

• Improved sleep in some trials but not in others (although no studies showed a negative effect on sleep)
• Improved sleep duration and efficiency (small to medium combined effect size) when sleep was measured objectively (e.g. with a wristwatch)
• Improved sleep quality (large combined effect size) and sleep duration (medium combined effect size) when sleep was measured subjectively (e.g. with a questionnaire)
• Improved sleep more in people with sleep or psychiatric disorders, and in healthy people exposed to a blue light-emitting screen

So, the limited evidence we have to date suggests that wearing blue light blocking glasses in the evening may be beneficial to sleep quantity and quality. How beneficial it is, will depend on lots of things.

If you currently have sleep or mental health problems you may see a bigger improvement.

If you use screens in the evening (that’s most of us, then) you may also see a bigger improvement from wearing blue light blockers. But it may depend on what you are consuming via the screen. Engaging with stimulating content (such as social media) on the device may disrupt sleep whether you block the blue light or not.  

I suspect wearing blue light blocking glasses in the evening will benefit sleep for most people, but the gain will probably be only marginal for many. Which makes it well worth doing. Because it’s the accumulation of marginal gains across many different areas that drives transformational change. Just ask Dave Brailsford.