Are LED Lights Bad For Your Eyes?

Countries around the world have been phasing out incandescent and low-efficiency light bulbs for more than a decade now, and though health hasn’t been a primary concern like affordability or cultural events, one question has floated around for some time:

Do light emitting diodes have an effect on your eyes?

More specifically, do LED bulbs affect your eyes? 

It’s a good question to ask whether bulbs, as a way to light the home or any environment, will have a negative impact on eyes and vision. The primary effect of LED lights is on sleep patterns under certain circumstances.

As with any matter in this technological era, there’s more to that answer, particularly in regards to the type of light that comes from LED light bulbs — blue light.

What Is Blue Light?

Blue light is part of the visible light spectrum just above ultraviolet light. It has high energy and a short wavelength between 400 to 450 nanometers. The name suggests correctly that it’s blue, but blue light can also be visible in light that appears white or another color.

LED bulbs emit visible light, including this blue light, but no ultraviolet light or infrared light shines from them. UV light damages DNA. 

Blue light is in phones, but keep in mind that the sun is the largest source of blue light. Yes, for countless years, the human race has walked this planet exposed to a source of blue light many times the luminance of the screens that cause people to get concerned and write think pieces about the psychological and physiological effects of screen time. 

The issue with blue light — wrote David Ramsey, MD, PhD, MPH, from Harvard Health Publishing out of Harvard Medical School — is that it has more energy per photon of light than other colors in the visible spectrum, i.e. green or red light. Because of that, at high enough doses, blue light is more likely to cause damage when absorbed by various cells in our body.

How Does Blue Light Affect People?

The impact of blue light can be good (believe it or not) and bad.

“Consumer electronics are not harmful to the retina because of the amount of light emitted. For example, recent iPhones have a maximum brightness of around 625 candelas per square meter (cd/m2). Brighter still, many retail stores have an ambient illumination twice as great. However, these sources pale in comparison to the sun, which yields an ambient illumination more than 10 times greater!” Ramsey continued.

Blue light wavelengths are beneficial during daytime because they boost attention, reaction times, and mood, according to a Harvard Health Letter. There was a 2007 study in the Journal of Neural Transmission that showed a “significant increase in alertness and speed of information processing could be achieved by blue light as compared to normal light.”

However, this increased alertness and attention comes with its host of problems.

“Because of its wavelength, blue light does disrupt healthy sleep physiology. Blue-light-sensitive cells, known as intrinsically photosensitive retinal ganglion cells, or ipRGCs, play a key role here, because they tell the brain’s master clock how light it is in the environment. That means, when you look at a brightly lit screen, these cells help set your internal clock for daytime-level alertness.” according to Assistant Professor of Optometry Phillip Yuhas at The Ohio State University.

The source of many concerns for the effects of LED lights on the eyes generally boils down to screens, particularly viewing habits of screens. Looking directly into a source of light over an extended period of time does have an effect on your eyes. To suggest otherwise would be irresponsible. 

In fact, there’s a name for it with screens: digital eye strain, which is the physical discomfort of staring at a screen for more than two hours at one time. 

According to a study from The Vision Council, nearly 60 percent of Americans use digital devices for five or more hours each day, 70 percent of Americans use two or more devices at a time, and 76 percent of Americans look at their digital devices in the hour before going to sleep. 

That will certainly have an effect on people.

There has been some research regarding whether blue light may cause damage to the retina, but the results have been inconclusive.

Per a 2016 article from the University of Alabama, “there is some early laboratory research using animal models that suggests excessive blue light exposure can damage some sensitive cell layers of the retina. There is no clinical evidence at the present time that links blue light exposure from digital devices to any pathology or disease of the eye.”