Blue light blockers claim to protect eyes from the harms of screen time, ranging from headaches to dry eyes. But what’s the science behind them?
Smartphones, computer screens, and even office lighting emit blue light. It is believed that this can suppress melatonin production and interfere with the circadian rhythm, making it harder to sleep at night.
Blocking the Wavelength
The premise behind blue light blocking glasses is that they filter out high-energy blue wavelengths of light emitted from screens and can trigger eye strain symptoms like headache, blurred vision, and dry eyes. However, a short review of the scientific literature reveals that these lenses don’t appear to reduce eyestrain brought on by prolonged screen use. Studies that randomized people to wear blue-light glasses or standard lenses during two hours of screen time found no differences in their eye-related symptoms.
Some researchers have found that blue light can interfere with the natural circadian rhythms that regulate your sleep cycle, tamping down melatonin, which is known to promote sleepiness. But a more straightforward solution to that issue is to put down your devices well before you go to bed and switch them to night mode, designed to lower the intensity of these light frequencies.
As for the alleged link between digital screens and eye damage, experts are still debating that. Some research suggests that reducing your screen time, taking 10-minute breaks every hour, using eye drops, and wearing blue-light filters at night can help mitigate any potential problems you might experience. But there’s also evidence that other approaches, like avoiding blue-light lighting in general and switching to natural light bulbs at home, can have the same effect.
Enhancing Melatonin Production
While blue light suppresses the sleep-promoting hormone melatonin, other light colors—such as green and orange—enhance it. For that reason, a few small trials have found that wearing amber-tinted glasses two hours before bedtime helps people fall asleep faster and log a longer, deeper night of sleep.
However, a new meta-analysis of 17 studies published Thursday suggests that the glasses likely don’t do much to reduce eyestrain or help people stay alert during screen time. And it’s unclear whether they benefit the sleep of those who don’t have chronic insomnia or circadian rhythm disorders like shift-work disorder and jet lag.
One trial, for example, gave participants BB glasses and a control pair that only had a partial blue-blocking effect to see if the glasses would improve their melatonin outcomes (melanopic lux, melatonin onset, melatonin profiles, phase angle). The BB glasses did result in a significant advance of melatonin secretion by 43 minutes over the baseline measurement, which aligns with previous research on the effects of BB glasses on melatonin in healthy nulliparous pregnant women.
Boosting Alpha Wavelengths
You’ve probably heard that blue light from screens can disrupt the circadian cycles that naturally control sleep and wakefulness. That’s why some people choose to wear blue light filter glasses, mainly before they go to bed. These lenses are designed to prevent bright light from interfering with melatonin production and other sleep hormones, and they’re also available in kids’ frames.
But despite the hype, the latest research indicates that blue light glasses don’t do much to reduce eye strain or help you fall asleep. According to a new study, they may cause more harm than good.
It is because most of the research on blue light glasses has been done on specific populations like pregnant women or those with certain mental health conditions, and it’s unclear how generalizable they are. While some patients find that blue light filters help, for those who have migraine headaches or are sensitive to light in general, amber or red lenses are a better option.
When you’re ready to try blue light-blocking glasses, decide on the frame material you want and what style fits your aesthetic. Then, decide whether you’d like to buy a complete pair or just a clip-on that fits over your current prescription reading glasses. You can also find options compatible with contact lenses and sports glasses, including a performance pair for yoga or the gym.
Suppressing Delta Wavelengths
Blue light-blocking glasses are often sold to help reduce digital eye strain. However, experts say that the frames are likely ineffective at this and that other steps should be taken instead.
Light is everywhere, from the sun shining down on you to your phone’s glowing screen. But it doesn’t just come in visible wavelengths; the spectrum also includes invisible radio waves, microwaves, and X-rays.
Each color of light reflects or absorbs different frequencies of electromagnetic radiation, and each frequency has its wavelength measured in nanometers. That means that when you look at a red shirt, the dye molecules in it have absorbed the frequencies of light in the violet/blue end of the electromagnetic spectrum. It makes the shirt appear red. In the same way, blue light filter lenses work by absorbing those frequencies.
Unfortunately, a recent meta-analysis of 17 studies found that blue light-blocking glasses don’t do much to relieve eyestrain or improve sleep. Instead, optometrists recommend other strategies, like taking regular breaks from screens and following the 20-20-20 rule, where you take a break every 20 minutes by looking 20 feet away for 20 seconds. They also encourage using artificial tears to prevent dry eyes, sitting about 25 inches away from the screen, and blinking more frequently to refresh your vision.