Blue light before bedtime can make it harder to sleep, and the screens on phones, computers, and televisions emit plenty of blue light. This is all true. But if you’re focused on blue light as a major problem affecting your sleep or your eye health, it’s time to step back and get a little perspective.
As Philip Yuhas, a professor of optometry, writes at The Conversation, blue light isn’t a uniquely technological evil. It’s part of sunlight, and your eyes are exposed to plenty of it all the time. You’re fine.
There are studies in mice that have found blue light can damage the eyes, but mice are nocturnal creatures whose eyes are different from ours. The pigments and the lenses of our eyes actually block blue light fairly well — so in a sense, we already have built-in blue blocking protection.
Adding more protection isn’t likely to help, though. You can buy glasses and screen filters that block blue light, but Yuhas points out they are probably a waste of money:
the products that my patients ask about do not block out much blue light. The leading blue-blocking anti-reflective coating, for example, blocks only about 15% of the blue light that screens emit.
You could get the same reduction just by holding your phone another inch from your face. Try it now and see if you notice a difference. No? Then it shouldn’t surprise you that a recent meta-analysis concluded that blue-blocking lenses and coatings have no significant effect on sleep quality, comfort at the computer, or retinal health.
The American Academy of Ophthalmology doesn’t recommend blue-blocking products, either. Instead, if you’re concerned about your eye health or your ability to get to sleep on time, you already know what to do:
Put the screens away at bedtime. Read a book or find something else to do.
While you’re using screens, take a 20-second break every 20 minutes to look at something 5 metres away (the “20-20-20" rule)
If you get dry eyes when you look at screens for a long time, use eyedrops labelled artificial tears.