If you have trouble sleeping or experience eyestrain, you might blame blue light, and you might be considering buying glasses that can filter it out. But before you do, here’s what Cori Jones, OD, an optometrist with Banner Health in Tucson, AZ, would like you to know about blue light and its effects on your body, as well as your eyes.
What is blue light?
Blue light is a wavelength of light found in sunlight, light bulbs and screens like your phone or TV. “It is normal and healthy to be exposed to blue light throughout your lifetime,” Dr. Jones said. “In fact, blue light from sunlight may promote normal eye growth and development in children.”
How does blue light affect your sleep?
Blue light helps regulate your circadian rhythm, or your body’s internal clock, so being exposed to blue light during the day can make you feel alert and awake, as you would want in the middle of the day. But when you’re exposed to blue light during the two to three hours before bedtime, it can suppress melatonin, a hormone that helps you go to sleep.
“Studies have shown that limiting artificial room lighting and screens before bed can improve sleep,” Dr. Jones said.
Blue-light-blocking glasses may also help improve your sleep if you use them before bedtime. If you decide to try them, choose a pair that is clear, not tinted. Tinted lenses can make it tough to see in low-light situations, so you’re more likely to trip or bump into something which could cause injury.
You can also use technology to reduce your exposure to blue light. “If you use your computer before bed and are having difficulty falling asleep and staying asleep, you can download a program like f.lux that blocks the blue light emitted from your screen after sunset,” Dr. Jones said. And on most smartphones, you can adjust your settings to filter out blue light after a certain time of day.
Is blue light linked to eyestrain?
If you have dry eyes and eyestrain from using screens, blue light probably isn’t to blame. “There is no scientific evidence that shows blue light from screens is harmful to the eyes,” Dr. Jones said.
It’s your rate of blinking that is most likely causing these problems. “You blink at a much lower frequency when you’re working on computers. It makes your tears evaporate, and that’s what causes your symptoms,” Dr. Jones said.
Instead of wearing blue-light-blocking glasses, take frequent breaks from your screen. Dr. Jones recommends the 20-20-20 rule: For every 20 minutes of screen time, look up at least 20 feet away for 20 seconds or longer. Artificial tears can also be helpful when you have to use your computer for a long stretch of time.
The bottom line
Blocking blue light before bedtime may help you sleep better. To do so, you can try blue-light-blocking glasses or filter out the blue light from your screens. However, there’s no evidence that filtering out blue light during the day helps your eyes. If you would like to connect with an eye care specialist, you can reach out to Banner Health.