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Hint: Stay off your phone at bedtime

Quick Notes:

  • Laptops and cell phones contain a blue light many people consider harmful to your eyes

  • People are buying blue light blocking glasses to help protect their eyes

  • However, a new study reports that the glasses aren’t as effective as you think

Have you ever considered how your laptop or iPhones could be damaging your eyes? The blue light in these devices is often blamed for eye damage and loss of sleep. The light contains high energy, and it can damage the delicate tissues of the human eye.

Several laboratories have studied and confirmed that prolonged exposure to high-intensity blue light damages retinal cells in mice. With this in mind, people think blue light is our biggest concern. They consider buying blue light blocking glasses, but these aren’t as effective as you think. In fact, your eyes aren’t damaged just by the blue light on your cell phones. You have something more severe to be worried about.

Think about the sun

Philip Yuhas, assistant professor at The Ohio State University, recently opened up about his research in conduct vision. He compares blue light and retinal damage to the sun. He explains that on a sunny day, it’s nearly 100,000 times brighter outdoors than your computer screen. Yet, people still think their computers and cellular devices are more damaging.

The original study on blue light reported there is damage to the retinal cells, but the study tested laboratory mice. Human eyes are different than rodent eyes. As Yuhas explains, we have more protective elements in our eyes, including macular pigments. We also have the natural blue-blocking ability of the crystalline lens. These absorb the blue light long before it ever reaches the retina.

Mice don’t have this level of protection. So, of course, their retinas are going to be damaged by blue light, as opposed to humans. When you hear a report that blue light is hurting your eyes, it’s not entirely accurate. It damaged mice, but you are still relatively safe.

“If being outside on a sunny afternoon likely doesn’t damage the human retina, then neither can your dim-by-comparison tablet,” says Yuhas.

Damaging your sleep

Blue light might not entirely damage your retina, but it does create other problems. For example, it disrupts your healthy sleep physiology. Blue-light-sensitive cells, known as intrinsically photosensitive retinal ganglion cells, trick your brain into thinking it’s still daytime. When you look at a brightly lit computer or phone screen, the cells alert your internal clock for daytime-level alertness. You’re no longer tired, even though your body needs to rest.

To improve your sleep, you need to dim all of the colors you see before you head to bed, not just blue lights. Many patients ask their optometrists if it would help if they bought blue light blocking glasses. The glasses have gained popularity as a way to heal eye strain and avoid a disrupted sleep cycle. Yuhas says his answer is always “no.” No, these glasses won’t help, but why not?

Blue-light-sensitive cells, known as intrinsically photosensitive retinal ganglion cells, trick your brain into thinking it’s still daytime.

According to Yuhas, the blue light blocking glasses don’t block out as much blue light as they’re advertised. In fact, they only block out about 15-percent of the blue light emitted from the computer or phone screens. Instead of purchasing these new, fashionable glasses, Yuhas offers other suggestions on how to make your screen viewing more comfortable and less harmful to your eye health.

How to help your eyes

To protect your vision, turn off your electronic devices before you go to bed. You should do this at least a half-hour before bedtime. Lower the brightness of your phone. If you notice any eye strain, make sure you have the appropriate glasses or contact lens prescription.

Also, consider how often we blink our eyes. We don’t just look at our computer screens while we’re working — we stare at them. Normally, we blink about 12 times per minute. When we’re staring at a computer screen, this shrinks to just six blinks. This causes inflammation on the eye’s surface, and our eyes might feel dry and tired.

Follow the “20-20-20” rule.

Take a 20-second break every 20 minutes to look at something 20 feet away in the distance. This brief break gives your eyes a chance to blink and relax. Your eyes are straining to work hard for you. The least you can do is give them a break every now and then.

A deeper dive – Related reading from the 101:

Learn more about how your cellular device is a distraction at bedtime.

Learn five additional ways to improve your eye health.