All day long — and long into the night — we stare at them.
The screens of our smartphones, our tablets, our e-readers, our computer monitors, our televisions are seemingly irresistible.
As they have proliferated, so have worries about how they are affecting our health. One of the main concerns is the blue light that these devices emit. It helps us see the screens, even in bright daylight. It is also a high-energy wavelength that can harm vision, disrupt sleep cycles, and lead to headaches or neck and shoulder pain.
A recent survey conducted on behalf of the American Optometric Association found that 88 percent of Americans know their vision can be harmed by digital devices. Yet still, they use them. Hour after hour after hour.
Andrea Thau, a doctor of optometry and president of the AOA, recently spoke to us about blue light and how to lessen its effects.
What is blue light?
Light in the visible spectrum has different wavelengths and different colors. The way you can see all the different colors – red, orange, yellow, green, blue - is through a prism. Blue light is very short wavelengths, the shortest of the visible wavelengths of light. Anything shorter is ultraviolet radiation, which we cannot see. We don't actually see blue light as blue, although sometimes when people use their screens in a dark room, they do cast a bluish glow.
Why is blue light such a worry now?
Blue light is emitted by everyday digital electronics, like tablets, smart phones, LED monitors and flat-screen TVs. In the past, people were not using these devices, so blue light wasn't a worry. But now, according to the AOA's American Eye-Q Survey, the average American spends seven hours a day on digital devices. Millennials spend an average of nine. People are holding these devices close to their faces and using them continually.
Does blue light harm us?
Yes, it can be harmful. It causes eye strain, blurred vision, dry eyes. Some people experience eye irritation – burning and stinging. It can cause headaches, neck and shoulder pain. For certain people, it can cause age-related vision problems.
Some people also have what's called transient smartphone blindness. It's caused by using the phone in the dark, such as while lying in bed, and looking at it through one eye. It causes this temporary sensation of blindness. This is not the appropriate way to use a smartphone.
Blue light also can cause sleep disorders. It disturbs your sleep cycle and can keep you awake. Blue light reduces melatonin production and tricks your brain into thinking it's daytime.
What can people do about it?
The AOA has several recommendations. First of all, the association urges patients to follow the 20-20-20 rule. When you're looking at a screen, take a 20-second break and look at something at least 20 feet away every 20 minutes.
You should maintain a comfortable distance from your digital devices. The proper distance is known as the "Harmon distance," named for Dr. Darrell Boyd Harmon. Hold your elbows at your side and hold your forearm parallel to the floor and put your device in your hand. People tend to hold their devices too close. You can use the zoom feature to see small print or details. Rather than bringing the device closer, make the font larger.
If you're using a computer screen, the center should be about 15 to 20 degrees, or four to five inches, below eye level. You should be looking down at the center of the screen. The top of the screen will be at eye level.
Also, power down before you turn in. Say goodnight to technology at least an hour before bedtime. This encourages what is called clean sleeping -- at least seven to eight hours a night. Sleeping consistently.
You can adjust your device. There are many apps and enhanced features, such as blue light filtering. Some devices have programs that will change the color of light that is emitted certain times of the day. Also, you may want to consider purchasing protective eyewear, such as blue-light filtering glasses.
You also should avoid glare, which can cause eyestrain and headaches. You can do this by using blinds or shades on windows, adjusting the lighting, or asking your doctor for anti-reflective coating for your eyeglasses.
Finally, make sure you blink often. Dry eye is a common problem. Nobody says, "I look at my computer." Everyone says, "I stare at it." It's true.
I'm getting the idea that people should see an eye doctor regularly, even if they don't have a specific vision problem that would require corrective lenses.
That's true. Doctors of optometry play an essential role in educating patients about eye health, including blue light exposure and its effect on overall health. People should be making sure they have a comprehensive assessment to devise a plan that will effectively preserve their vision.
Doctors of optometry also can protect your overall health. In 2014, my colleagues found 240,000 cases of diabetes just through eye examinations. Other diseases that can be detected through an eye exam – if they haven't already been diagnosed – include thyroid problems, high blood pressure, sickle-cell anemia, brain tumors, aneurisms, leukemia. The eye is the only part of the body where a doctor can see exposed blood vessels without having to cut you open. Any disease that affects the blood vessels in the body would show up in the eye.
There is much more to an eye exam than just getting glasses and seeing clearly. Optometrists are trusted health professionals. Our eyes are very precious and they're under an intense amount of stress and demand. It's really important to protect our vision. We have only one set of eyes, and they have to last us a lifetime.