LED lights are often praised for being energy efficient and free of toxic gases and materials but how safe are LED lights for your eye health?
How much of a concern is the blue light produced by LEDs and their potential flicker?
Before you become too concerned, as long as you are buying certified LED lights you don’t need to worry about any serious health hazards.
What you might want to think about is how prolonged exposure to certain LED models affects your eye health.
Read on to learn more about eye health in relation to LED lighting.
Flicker in an LED Light
To understand flickering in LED lights you need to understand how an LED works. Unlike other types of lights, an LED runs on full power at all times even when it is dimmed.
What we perceive as dimming in an LED is actually very rapid switching on and off at a specific speed which our eyes then register as a dimmed light. The rate at which the LED light switches on and off changes depending on the dimming level.
The reason why we can only see a dimmed light is because the frequency at which the LED light switches on and off is too fast for our brains to process. The only time that you will notice a flickering caused by a dimmer is when there is too much difference between the frequency of the dimmer and the LED.
LED headlights can also flicker, but this generally a technical system issue rather than a dimming attempt.
The second reason why you might notice a flickering LED is because the LED is not fitted with capacitors to make up for the polarity switch in the AC current of most households.
This is generally only the case with cheaper LED designs.
An LED actually runs on DC current and has a driver that changes the current from AC to DC.
However, the driver alone is not enough to compensate for the change in electrical current which is why some LED designs produce flicker.
What Are the Risks of Flicker?
In some cases, you won’t even notice that an LED light flickers because the frequency is too fast for you to register. Despite not knowing whether there is flicker, your eye health might still be affected by it.
Flickering lights are associated with tiredness, headaches and strain on the eyes.
People with light sensitivity like the elderly or people suffering from seizures are also more sensitive to flicker in lights.
If you notice any of these systems after prolonged exposure to certain light and there is no other underlying cause, you might be dealing with a flickering light.
So how do you measure something that you cannot see?
The professional way to measure flicker is using an oscilloscope but you can also record flicker when using a video camera that has a fast enough frame rate. Other signs of flicker are darker rings on the edge of a picture or when moving objects seem to be interrupted.
The best way to avoid a flickering LED light is to only buy LED bulbs that are certified as flicker free.
Blue Light in an LED Light
Blue light is commonly associated with sleep issues and was recently featured on the Harvard University website with their findings.
Blue light is part of the spectrum of LED lights so yes, LED lights produce blue light, too. Personal devices like mobile phones, tablets, computers, and televisions are all known for emitting blue light and many of these devices use LEDs as backlight.
LED light bulbs can also emit blue light but you have more control over a light bulb. In other words, you can also take more control over how much blue light is emitted by an LED light bulb.
When you are concerned about blue light in an LED light bulb, look out for the following things; color rending index (CRi), color spectrum and color temperature.
Lights with a high CRi value show the true color of objects better because it emits a higher level of red light.
More red light also means less blue light so you can use the CRi as an indicator of how much blue light the light bulb produces.
The melanopic to photopic lux ratio, or m/p ratio for short, is an indicator of how much the light source encourages the production of melanopsin. Look for a ratio of 0.4 or less if you are concerned about blue light exposure.
Melanopsin is the chemical that controls our alertness level and exposure to blue light increases the production of melanopsin.
This is why scrolling on our phones before going to bed makes you feel less sleepy and why you shouldn’t sleep with some lights left on.
The color of light emitted by a light source is measured in Kelvins. Bright white light and daylight equivalent light has a higher kelvins value of 4000 kelvins or more while softer more yellow light has less than 3000 kelvins.
The presence of blue light increases as the Kelvins increase. So, choose light bulbs that produce a warm white or yellow white color with less than 3000 kelvins to minimize blue light exposure.
What are the Risks of Blue Light?
As mentioned, exposure to blue light encourages our body to produce more melanopsin.
Melanopsin is a hormone that makes us feel more alert.
We actually receive blue light from sunlight, too and it serves a purpose in our circadian rhythm. Blue light from daylight triggers our body to wake up and be active but as the daylight diminishes our body receives the cue that it is time to go to sleep.
The problem with prolonged blue light exposure is that it tricks our body into thinking it is still daytime. Our natural circadian rhythm is disrupted which can cause sleep issues for certain people.
In short, we need blue light but we should control blue light exposure during nighttime to keep our natural circadian rhythms intact.
In conclusion, LED lights are completely safe to use but be careful with prolonged exposure. Make sure that you use flicker free LED lights and limit your exposure to blue light at nighttime.