On Monday, August 21st, beginning just after 10:15 a.m. PDT, it will get dark enough that city lights will turn on, the temperature will cool slightly, and some nocturnal creatures will start to stir. It’s a total eclipse of the sun, the first anyone has seen in 99 years.

This once-in-a-lifetime event will be visible within a 70-mile-wide path across the country, stretching from the Oregon coast to the beaches of South Carolina. Even those of us who are not within the path of totality (check the geographic map on NASA’s website) will still get an impressive show, as over 80% of the sun will be eclipsed by the moon.

A total solar eclipse is one of nature’s most awe-inspiring sights, one that ancient civilizations regarded as a heavenly sign. It’s also an event that comes with a warning—don’t look directly at the sun as it is eclipsed, as this could damage your eyesight. These warnings have me thinking more about my eyes, and how we need to protect them for a lifetime.

Nowadays, one of the first things we can do to maintain healthy vision is to be aware of our exposure to blue light. Blue light has become an increasingly important topic over the last several years as our collective use of digital devices has steadily increased. It’s a fact of modern living—many of us spend a good portion of our days (and nights) looking at digital screens. And that means our eyes are more exposed than ever to blue light.

When Your Eyes Get the Blues

About 30% of sunlight is blue light—light rays spanning a spectrum of colors make up the rest. Each color along the spectrum is associated with a particular wavelength. Longer wavelengths are less energetic, while shorter wavelengths are more energetic. Blue light’s shorter wavelengths and higher energy rays scatter more easily in the atmosphere than other visible light rays, which is why the sky looks blue on clear days. It’s also why we get eyestrain when looking at computer screens that emit a lot of blue light. These shorter, more energetic wavelengths can cause a flickering effect that makes it harder to focus, which can be exhausting for the eyes.

Some blue light exposure is actually beneficial, as blue light plays important roles in regulating our circadian rhythms that support a healthy sleep cycle. Too much exposure too late at night, however, can have the opposite effect. Blue light is often used in light therapy to support alertness and mood.

The eye’s cornea and lens naturally block harmful UV light. But blue light passes right through these initial guardians and reaches the light-sensitive retina, where overexposure can be harmful. Sources of blue light are now everywhere, from energy-efficient bulbs and compact fluorescent lights (CFLs) that illuminate our homes to the light-emitting diodes (LEDs) that illuminate our smart phones, tablets, laptops, computers, e-readers, and television screens. This increased exposure to blue light has many researchers concerned about the short-term and long-term effects of blue light on eye health.

Ways to Limit Blue Light Exposure

1. Use filters for screens and devices

A number of products for your phone/device can help block blue light. Physical screen protectors that attach to the screen of your phone or device screen and filter out blue light are one option. Digital apps that, once installed on your phone/device, tint your screen to neutralize blue light are another option. Many of these apps also automatically adjust the light emitted by your screen according to the time of day, your geographical location, and the seasonal position of the sun.

2. Wear computer glasses and special lenses

“Computer glasses” are available that have yellow-tinted lenses, which help block blue light from entering your eyes. Glasses with special anti-reflective lenses are a related option; they reduce glare, increase contrast, and limit blue light while using computers and other digital devices.

3. Get plenty of lutein, zeaxanthin, and omega-3s

Lutein and zeaxanthin are dietary carotenoids. When we consume them, they’re deposited in the retina of our eyes, where they help filter out blue light. While the typical diet provides 1-2 mg lutein, research suggests that we need 10 mg of lutein and 2 mg of zeaxanthin each day for optimal health.* Omega-3s are essential fatty acids. The omega-3 DHA is especially important for the eyes, and is more concentrated in eye tissue than in any other part of our bodies. Our bodies don’t make lutein, zeaxanthin, or omega-3s, so these eye-friendly nutrients must be consumed through diet or supplementation.

A lot has changed in the world since the last coast-to-coast total solar eclipse 99 years ago. Among those changes is the kind of light our eyes are exposed to now, which is quite different than it was in previous eras. Being mindful of our exposure to blue light is one simple thing we can all do to proactively support our eye health.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

References
Mol Vis. 2016 Jan 24;22:61-72.
J Sci Food Agric. 2010 Jan 15;90(1):2-12. doi: 10.1002/jsfa.3785.
Prog Retin Eye Res. 2005 Jan;24(1):87-138.