If you’ve recently bought a new pair of prescription glasses, you’ve probably seen arguments for anti-blue lenses that are believed to reduce eye strain and sleep disturbances associated with using digital screens. But do they live up to the hype? We will take a look.
There are several claims about the benefits of glasses that filter blue light (which we’ll cover below), but first, let’s take a look at how glasses filter blue light.
It’s pretty simple: Each blue light blocking lens is tinted in a way that lets in more red and green light and less blue light. Usually not all blue light is blocked, and the amount of reduced blue light will vary depending on the lens type and manufacturer.
When you wear blue light filtering glasses, what you see is yellow colored light (a combination of the passing red and green light). You will see the world with a more yellowish tint.
To determine the effectiveness of blue light filtering lenses, you need to separate the different claims about them. A common claim is that they reduce eye strain when looking at screens on devices like smartphones, tablets, and computers.
According to American Academy of Ophthalmology (AAO), there is currently no scientific evidence that light from digital screens damages the eyes or causes strain. Indeed, the organization quotes a recent study this suggests that there is no reduction in eye fatigue with blue light filtering lenses compared to completely clear lenses.
Instead, the AAO recommends reducing eye strain by reducing screen time and taking regular breaks when using your digital devices.
A 2019 study support this assertion somewhat. LensCrafters offers a solution, claiming that its blue light filtering lenses can help prevent such disruption. But fortunately, in the study the cited company, participants’ melatonin levels returned to normal levels within 15 minutes of stopping viewing screens – no special glasses required.
The assumption behind the disruptive nature of artificial blue light sleep is that the Earth’s natural day and night cycles regulate our internal clocks, giving us energy during the day when the sunlight is brightest and naturally sleepy at night when the light is weak. If you stay awake late looking at your bluish tablet or smartphone, you may be sending the wrong signals to your brain, telling it to be alert when it should fall asleep.
However, if this assumption is correct, you need exposure to both blue light and warm yellow light to function properly throughout the day. It is no exaggeration to suggest that wearing anti-blue lenses all day could preventing you from getting necessary blue light exposure needed to help you feel alert. You might feel asleep all day by wearing them.
So this means that if you have blue light blocking glasses, you might be better off wearing them only in the evening. A recent systematic study suggested that blue light glasses have a positive effect for people with insomnia when worn in the evening. But this study also suggests that blue blockers are more effective when worn specifically as part of active medical treatment for insomnia instead of a 24-hour lens solution for your regular glasses.
And in the end, wearing prescription anti-blue glasses might not matter because the glasses are not standardized between vendors, according to an article in the Harvard Heart Letter. This means that there is no guarantee that the blue light lenses you buy will block the right frequencies or the right amount of blue light to have any effect. Your mileage may vary.
A cheaper way to improve eye health and sleep
With the mixed reputation of glasses that block blue, there is a cheaper way to keep your eyes healthy. For eye strain, take breaks every 20 minutes while using a digital screen. And to avoid disruption to sleep caused by screens, experts recommend that you don’t use devices like smartphones, tablets, and computers 2-3 hours before bedtime.
If you are using screens at night, use a warm light filter such as Apple’s Night Shift or Microsoft’s Night Light, or Google’s Night Mode to reduce the amount of blue light coming from your screen. Also, if you like to read digital books at night, consider buying a Kindle. E-readers that use electronic ink have screens that are easy on the eyes.
More pleasing to the eyes
Anyone who has been around for more than a few decades has seen health fads come and go. Some of them involve gadgets, some follow new technologies (like television and computers), and some react to successful studies that are over-exaggerated and sometimes later contradicts.
The best time to be skeptical about a health claim that involves buying a product from someone who is not a doctor is when it is a relatively new. Right now, the fashion for glasses that block blue light is scorching, as frequent use of screens in bed is a relatively new thing. In the years to come, the trend may fade as people find blue light glasses less beneficial than expected, or as the next technological innovation renders the scenario obsolete. Alternatively, other scientific studies could support the beneficial effects of blue light glasses. Solid science takes time.
In the meantime, follow your doctor’s advice and try to do everything (including screen time) in moderation. Stay healthy!